Lucilia Robineau-Desvoidy,

Whitworth, Terry, 2010, Keys to the genera and species of blow flies (Diptera: Calliphoridae) of the West Indies and description of a new species of Lucilia Robineau-Desvoidy, Zootaxa 2663, pp. 1-35: 17-18

publication ID 10.5281/zenodo.276279

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scientific name

Lucilia Robineau-Desvoidy


Genus Lucilia Robineau-Desvoidy 

There are four genera in this subfamily but this is the only genus in the New World.

Diagnosis. Ground color shining green, blue, or bronze, though one species, L. problematica Johnson  is duller colored; suprasquamal ridge posteriorly with a shining sclerite with a cluster of setae; lower calypter bare.

Discussion. In the West Indies there are 10 species of Lucilia  known, five of which are endemic to the region. Most published accounts on this genus in the Neotropical Region use the synonym Phaenicia Robineau-Desvoidy, 1863  . Lucilia  throughout the West Indies can be difficult to identify to species, especially the eight species with two postsutural acrostichal setae that have few distinguishing characters. Specimens are often in poor condition so a subtle character like color can be difficult to interpret. Characters used include color of basicosta and calypter and patterns of microtomentum on abdominal tergites. The distribution of tibial setae is somewhat variable and cannot be relied upon to separate species. The shape of male genitalia tends to be similar among species in this group and is of minimal value to distinguish most Lucilia  in this area. The ovipositors from species in this group also exhibit little variation between species.

Six little known species were selected to study in detail, comprising L. cluvia  , L. eximia  , L. fayeae  , L. lucigerens  , L. retroversa  , and L. rica  ; the latter four known only from the West Indies. For convenience, they are referred to as the L. eximia  group. In five of the species, the male genitalia, including the epandrium, surstyli, and cerci are densely covered with long curly setae. Only L. cluvia  has somewhat sparser setae on the male genitalia. The setae are often so dense that it can be difficult to see the surstylus and cercus clearly when they are drawn down in the specimen making it necessary to perform a dissection. The surstylus tends to be digitate, though it is broader and usually sharply turned inward in L. retroversa  ( Fig. 49View FIGURES 38 – 49). Female specimens are even more difficult to distinguish; those in poor condition may be unidentifiable.

Figures and descriptions of the phallus and other male characters and ovipositors for six species of the L. eximia  group which occur in the West Indies are given. They are surprisingly uniform in appearance so shared characters are discussed here and not repeated under each species.

Male genitalia. The phallus appears to be the same general type for each species; see Fig. 56View FIGURES 52 – 61 for terms. They are closest to the “ L. caesar  type ” as described by Rognes (1991). Epiphallus originates toward the anterior end of the basiphallus. Paraphallus long and slender and apically curved down with dentate tips. Hypophallus has low dentate ridges and no projections. Acrophallus long and slender ending in a dentate covered tip. No lateral ducts evident. Pregonite slender, with three setae, the distal seta in the apical position; postgonite has a single basal seta. Ejaculatory sclerite small and slender with a flattened expansion at the end, as in Fig. 64View FIGURES 62 – 72. 62, 63.

Variation in surstyli. In the process of describing two new species of Lucilia  ( L. lucigerens  and L. retroversa  ) from the West Indies, James (1971) identified a character he described as “geniculate outer forceps.” In this condition, surstyli curve sharply inward midway to about a 90 ° angle similar to the condition shown in Fig. 49View FIGURES 38 – 49. When this study was begun, this character was observed in specimens of other species of Lucilia  in the region, including L. cluvia  , L. eximia  , L. fayeae  and L rica  . Initially it was suspected that L. cluvia  -like specimens in the region belonged to a separate species from those in North America based in part on this condition. Unfortunately it proved to be highly variable within species, and the sharp bend disappeared when specimens were heated in KOH and dissected. Lucilia retroversa  was more likely to retain a distinctive bend than the other species though even that was variable ( Fig. 49View FIGURES 38 – 49).

I have concluded that the bend in the surstyli is not useful for species distinctions because it is too variable and probably caused by environmental factors. In hot, humid climates, many collected specimens of Lucilia  are very moist and often appear teneral. I suspect that the drying process in recently killed specimens can sometimes lead to the warping of the surstyli. I also observed this condition in some specimens of Lucilia  from the Florida Keys and Central America.

Female genitalia. Ovipositors in the L. eximia  group are composed of three segments, 6, 7 and 8. T 6 is one complete sclerite, while T 7 and T 8 are more or less divided; sternites are single sclerites. Epiproct, hypoproct and cerci similar in all six species; see Fig. 88View FIGURES 88 – 90 for characters and see ovipositor figures cited under each species. T 6 broad, with paired spiracles and a strong row of setae on the rear margin, and no mircrotrichia on this tergite in any of the species. ST 6 tends to be pear-shaped with dense setae on the rear third or more, and mircrotrichia are present on the rear portion of this sternite in all species. A dashed line on the rear of ST 6 in each figure shows how far forward the microtrichia are found. T 7 separated by a membranous area that extends nearly to the rear of the tergite with a row of setae on the posterior margin. ST 7 elongate, often a little longer than T 7 with a row of strong setae at the rear. T 8 divided into two distinct tergites, each section with strong setae posteriorly. ST 8 longer than T 8 with a strong row of setae posteriorly. Epiproct, cerci and hypoproct covered with setae and mircrotrichia. Intersegmental and most pleural membranes have microtrichia which are directed forward and vary in shape by segment; selected areas are shown in each figure.