80 



were absent in the pupa examined. The labial palpi are represented 

 by a small triangular area, but it is not known whether or not maxil- 

 lary palpi are retained. The maxillae are much shorter than in the Hes- 

 periidae, being only about two thirds the length of the wings, but this 

 indicates nothing as to their position, as both generalized and special- 

 ized pupae possess short maxillae. None of the other appendages are 

 longer than the maxillae except the wings, which lie adjacent on the 

 meson caudad of the maxillae. The epicranial suture is present and 

 the vertex is of equal length throughout, being about one fifth the 

 length of the prothorax measured on the meson. The entire body sur- 

 face is covered with a whitish bloom, and on the dorsum of abdominal 

 segments 7-10 there is in addition a dense covering of rather coarse 

 setae. The pupa examined was 40 mm. in length and about 10 mm. 

 in breadth, and belonged to the genus Megathymus. 



The following species was examined : 

 Megathymus yuccae Boisduval and Le Conte. 



Family Hesperiidae 



The Hesperiidae retain considerable freedom of motion of the ab- 

 dominal segments, and in many genera it would seem that dorsal 

 motion is possible between the third and fourth abdominal segments 

 and that the seventh abdominal segment is free in the male, or at least 

 that they have only recently lost the power of motion. The epicranial 

 suture is present in all genera, and the vertex is about one fifth the 

 length of the prothorax measured on the meson, while the lateral mar- 

 gins are considerably longer. The labrum in most genera is consid- 

 erably cephalad of its normal position. The antennae never reach to 

 the caudal margin of the wings but are from two thirds to three 

 fourths of their length. The 'prothoracic legs are about half the 

 length of the wings, the mesothoracic usually two thirds of the same, 

 while the metathoracic pair is seldom visible. The maxillae always 

 extend to the caudal margins of the wings and frequently consider- 

 ably beyond. The mesothoracic spiracles usually have a peculiar kind 

 of plug or plate which seems to form an external closing apparatus 

 or guard, while some have prominent tubercles caudad of the opening, 

 usually with a dense covering of setae. The thorax and abdomen 

 usually have a more or less dense covering of setae, and some of the 

 species have the entire body covered with a whitish bloom, which is 

 of comparatively rare occurrence among lepidopterous pupae. The 

 abdomen frequently has a furrow on the dorsum between the ninth 

 and tenth segments, similar to the furrows found in the Pyralididae 

 but never so deep. The cremaster in all genera is more or less trian- 



