NO- 3569 SOLDIER FLY LARVAE — McFADDEN 5 



imder laboratory conditions and that the pupal stage may last from 

 2 weeks to 5 months. May (1961), also working with 77. illucens, 

 gave more precise figm-es for the duration of the various stages in 

 the life cycle and, in addition, was able to complete the life cycle 

 successfully. 



Eggs. — ^Eggs usually are laid in early spring by females that have 

 ove^^vintered as larvae. When first laid, the eggs are pale yellow but 

 become progressively darker as the hatchmg date approaches. The 

 actual time required for hatching varies from 5 days to 3 weeks. 



Hart (1895) mentions that the eggs of Odontomyia are "cigar- 

 shaped," but this is not the case throughout the family. Wesenberg- 

 Limd (1943) reports that the eggs may be flattened or highly arched 

 or in the form of a "regular" egg. In addition, he mentions that the 

 eggs usually are placed in a distinct group or clump (the number 

 varying with the species) on vegetation overhanging water, in the case 

 of aquatic forms, or on decaying organic matter, in the case of terres- 

 trial forms. Wesenberg-Limd (1943) also mentions that the eggs of 

 Stratiomyidae are difficult to distinguish from those of Tabanidae. 



Larvae. — Newly hatched larvae were noted by Irwin-Smith (1921) 

 to molt as soon as they emerged from the egg. Active feeding com- 

 menced unmediately. As stated previously, the duration of the larval 

 state is unlmown but the larvae of the majority of the northern 

 Nearctic species appear to be fully mature by fall. These mature 

 larvae are probably the overwintering stage, as pupation does not 

 occur until the following spring. 



Larvae in each of the subfamilies exhibit a varying degree of simi- 

 larity with respect to then- feeding habits (James, 1960), but there is 

 considerable variation in habitat selection by species within the 

 subfamiUes. Thus we have papers by Packard (1871), Lucas (1879), 

 Griffith and Packard (1882), and Brues (1924, 1928, and 1932) 

 recording the occurrence of larvae in salt water and in hot springs 

 and lakes. Pearson (1883) reported a larva that was found on an 

 exposed part of ocean beach, and Florentin (1899) found a great mass 

 of larvae in excessively saline pools. 



The sum of our knowledge on habitats for the larvae of the North 

 American genera of Stratiomyidae is presented in condensed form 

 in table 1. Except for genera such as Actina, which are known only 

 from some other part of the world, the references are primarily to 

 North American workers. It is hoped that this table will not only 

 be an aid to collecting larvae but will also be a guide to the needs 

 for future studies within the family. Additional information on 

 biology of the larvae is given under the species descriptions. 



