107] LEPIDOPTEROUS LARVAE — FRACKER 107 



bb. Dorsum of thorax not flattened nor triangular; anal prolegs not 

 greatly elongated ; head usually as large as prothorax. 



NOTODONTINAE 



Melalophinae. This subfamily includes the one genus Mdalopha 

 (Ichthyura). The six species may be distinguished by the characters 

 given by Packard, (1895). 



Pygaerinae. The larvae of Datana are well known in all parts of the 

 United States. As the colors change at each molt the species are hard 

 to separate. Packard gives a key to them which may be used with more 

 or less success, and his figures are invaluable. He was acquainted with 

 the larvae of all described species except rohusta, modesta, and chiri- 

 quensis. D. robusta is very similar to D. contracta but the stripes are 

 dark brown instead of creamy white and the prothoracie shield is black 

 instead of yellow in the last instar. 



Cerurinae. Two genera, Harpyia and Cerura, whose larvae are 

 very similar, compose this group. The long stemapoda, or modified 

 anal prolegs, distinguish them at a glance from other Notodontidae. 

 In Cerura scitiscripta the metathorax has a single median prominence, 

 and in C. occidentalis there is a bifurcate one. The metathorax of the 

 species of Harpyia is without prominences. All have a dorsal reddish 

 somewhat broken vitta running the entire length of the body and reach- 

 ing in some places as far ventrad as the spiracle. In H. cinerea this 

 vitta is wanting on the metathorax but in the other two species it is 

 continuous from thorax to abdomen. Its lateral margins are convex 

 on the mesothorax of H. scolopendrina and concave in H. horealis. 



Notodontinae. At first glance the genera which are grouped to- 

 gether under this name seem rather heterogeneous. The wing venation 

 of the adults is as various as the form of the larvae. Nevertheless a 

 logical separation of Gluphisia and the Heterocampinae seems almost 

 impossible. The former is very closely related to some of the Notodon- 

 tinae as Packard limited the group. The species of Heterocampa form 

 a series of transition stages from typical notodoutians to the peculiarly 

 specialized larvae of Schizura and Hyparpax. This is in striking con- 

 trast to the distinct separation of the Pygaerinae and the Ichthyurinae 

 from other members of the family. The long stemapoda in early stages 

 of Fentonia (Macrurocampa) seem to indicate that even Cerura and 

 Hayrpia should be included here. Other structures, however, make the 

 line of separation distinct. The various genera may be distinguished by 

 means of the following synopsis. The comparative clause in the first 

 division is due to the peculiar dorsal series of gibbosities of Nerice, a 

 genus which clearly belongs in the second group. 



