^'^- ^^"^ SOLDIER FLY LARVAE — McFADDEN 3 



Rearing was simplified by collecting in the spring, when larvae 

 were usually in the last instar, about to pupate, or had already 

 pupated. Larvae and pupae held for rearing were placed in 5-dram 

 vials fitted with cotton stoppers. A small amount of the substrate 

 in which the animal was found was placed in the vial before adding 

 the specimen. Distilled water was added occasionally to maintain 

 moist conditions. Larvae and pupae were always reared individually 

 so that emerging adults or parasites could be associated with the 

 respective larval or pupal skin. The adults were then identified and 

 associated with the larvae that had not been reared, and thus the 

 identity of these larvae was determined. This is by no means a 

 foolproof system for identification, but in most instances it can be 

 relied upon because of the gregarious nature of the larvae. 



In observing preserved specimens, I frequently found that many 

 morphological characters that are used in distinguishing the various 

 taxa were obscured by deposits of calciiun carbonate and environ- 

 mental debris. The larvae were quickly cleaned of most of the 

 debris by soaking them in 10 percent hydrochloric acid (Lundbeck, 

 1907, and Johannsen, 1935). Active effervescence always accom- 

 panied this treatment. 



The head of the larva was prepared for study by removing it from 

 the body and placing it in a test tube containing 2 percent potassium 

 hydroxide. The tube was placed in a beaker of water and boiled 

 slowly for 2 hours. The heads then were washed in glacial acetic 

 acid, dissected, and mounted on a slide. Photomicrographs were 

 prepared using the technique described by Howden (1955). 



Historical Resume 



Frorn 1720 to the present, nimierous papers have been written 

 on various aspects of stratiomyid natural history as well as on mor- 

 phology and physiology of the larvae. Rather than attempt to 

 condense a voluminous literature in a few paragraphs here, I shall 

 discuss these works under their appropriate sections of biology, 

 morphology, phylogeny, and classification. 



Studies on the biology and systematics of larval Stratiomyidae 

 can be divided into 2 rather distmct periods. 



The first period (1720-1868) was devoted to the description of 

 local faimas.^ In most mstances larvae were associated mth adults 

 through rearing so that correct identifications were obtained; however, 

 no attempts at classification were made nor were other generalities 

 presented. 



The second period, which was initiated by Brauer (18G9), was 

 characterized by the incorporation of biological features and the 



