1892.] ENTOMOLOGICAL NEWS. II5 



broods in one season more usually annual, and rather more rarely 

 passing more than one year in the larva state. 



The imagos have moderately long antennae, gradually and va- 

 riably thickened medially, more slender apically, the tips often 

 with a brush of hair. Rarely they are setaceous, or thread like. 

 In the male they are often furnished with lateral tufts of bristles 

 and sometimes with lamellae or pectinations. The head is vari- 

 ably developed, usually quite small; ocelli present; tongue vary- 

 ing from a well developed organ to a mere rudiment. The latter 

 character is of great importance in the systematic study of the 

 family. The thorax is usually robust and quite closely scaled. 

 The abdomen is long and comparatively slender in most cases, 

 often brightly banded. The wings are narrow, the primaries 

 longer than, but not so broad as the secondaries. They are 

 wholly or in part transparent as a rule, and this, combined with 

 the bright, banded maculation, gives them a wasp-like appearance 

 that may be protective. 



The venation is distinctive, and of a low type. The median 

 cell is well developed, and all, or nearly all, the veins arise from 

 it separately. The internal vein is wanting, or forms the internal 

 margin itself In the secondaries we have a very similar type of 

 venation; but here the costal vein is missing, and there may be 

 two or three internal or free veins. Vein 5 is often absent as well. 

 The legs, as a whole, are well developed, the posterior often 

 markedly longer than the others, while the anterior are actually, 

 as well as relatively, short without being weak. 



The sexes sometimes differ quite markedly, not only in size, 

 but in color and maculation, and it is not unlikely that some of 

 our numerous species represent sexes of others. In habit the 

 insects are diurnal as a rule, but have been occasionally attracted 

 to light. The characters of most of the American genera have 

 been given by me in " Entomologica Americana," iv, 9-13. 



Somewhat allied to the Sesiidae, in habit and appearance, are 

 the Thyridae. The relation between the two is superficial merely, 

 and vanishes on study. They are small and stout, with long, 

 strong tongue, large, projecting, bristly palpi and spindle-formed 

 antennae, the basal joint much enlarged. In the male they are 

 singly pectinated. The ocelli are wanting. Thorax robust, ab- 

 domen conic and comparatively short. The legs are stout, clothed 

 with long, stiff hair, middle tibiae with one, posterior with two 



