Dennis, Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2013, Review and analysis of information on the biology and morphology of immature stages of robber flies (Diptera: Asilidae), Zootaxa 3673 (1), pp. 1-64: 6-7

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Subfamily Laphriinae 

The majority of Laphriinae  females deposit 2 to 18 eggs in dead tree trunks or other wood. Andrenosoma fulvicaudum (Say)  oviposits primarily on pinyon pine trees ( Pinus monophylla Torr. and Frem.  ) still smoldering from fires and the females have sensory organs (“cercal organs”) on their ovipositors that aid in the selection of oviposition sites such as Coleoptera  burrows. Cerotainia albipilosa Curran  oviposits on vegetation. Londt (1994), based on the morphology of the ovipositor, speculated that some genera might drop eggs onto the ground. Eggs of Laphriinae  species are bright amber, brown or reddish brown. They are usually oval, but can be round or elongate. The oval to round eggs range in length from 0.29 to 0.50 mm and width from 0.25 to 0.48 mm; more elongate eggs range in length from 0.75 to 0.93 mm and width from 0.55 to 0.60 mm.

Most Laphriinae  eggs have surface features consisting of different shapes of polygons, often with raised ridges and reticulate sculpturing. Some also have pimples or spine-like structures on the surface. Most genera have aeropyles, some of which are cone-shaped. There are one or two micropyles located in broad, smooth areas or in narrow areas with low ridges.

Fisher (1986) indicated that no completely smooth eggs have been reported for the tribe Andrenosomatini (as Andrenosomini), but some other Laphriinae  have smooth eggs. The chorion features or sculpturing begins at the edge of the smooth micropyle area or posterior to it if there is a “corona” of pale, flocculent or scaly material. These features are usually most distinct in the apical half of the egg, with the remaining half patterned or smooth, although some species have eggs with a chorion that is completely covered with sculpturing.

Under laboratory conditions at a constant temperature of 25 °C, the egg stage of Andrenosoma atrum (Linnaeus)  lasts up to 50 to 56 days ( Musso 1978, 1981b, as A. atra  ).

Laphriinae  larvae and pupae are usually found in decaying trees and tree stumps, or under scorched bark of pinyon pine trees ( Andrenosoma fulvicaudum  ). The larvae are reported to feed on Coleoptera  larvae from the families Buprestidae  , Cerambycidae  , and Curculionidae  .

The larval stage for Choerades  lasts for up to 2 years. No information was found on the length of the pupal stage.

Detailed morphological information is available on a number of species, in particular in the genera Andrenosoma  and Laphria  . The most detailed descriptions of Andrenosoma  larvae are in Musso (1978, 1981b). The most detailed pupal case descriptions with figures are in Dennis & Barnes (2012), Dennis et al. (2008 a), and Musso (1981 b). There is general descriptive information for other genera.