310 Annals Entomological Society of America [Vol. IX, 



the size of the larva and the scant remains of the abdomen, 

 it would seem that the larva had almost filled the entire abdo- 

 men. The cephalothorax and legs were also eaten out so 

 that the remains resembled a cast skin, except for the fact 

 that the cephalothorax was not broken. The smallest larva, 

 which was 6 mm. in length, had emerged under similar conditions 

 but from a smaller spider. In the third case no remains of a 

 spider were noted. 



Since the foregoing notes were written, five larvae of this 

 species have been found to be parasites of Lycosid spiders. 

 Concerning the identity of these, Mr. Nathan Banks states 

 that he is almost certain the species is Lycosa pratensis Emer., 

 the doubt of the question being due to the partial destruction 

 of the specimens by the parasites. 



The larvae vary in length from 6 to 8 mm. and are oval in 

 form with a strong constriction marking off the smaller cephalic 

 end (Fig. 8). They are of a creamy white color and on the 

 dorso-meson show four dark areas which pulsate in a slow, 

 rhythmic manner. The body-wall is soft and delicate, the 

 external surface being smooth and sticky, causing the web and 

 small particles of dirt to adhere to it. The segmentation of the 

 body is not very distinct; however, the cast skins show twelve 

 body segments. The four anterior segments are not as well 

 defined as the others and seem to be softer and more delicate. 

 The second segment bears a pair of closed spiracles which con- 

 nect with large tracheal tubes. On the ventral surface of the 

 fifth to the eleventh segments are seven pairs of padlike areas 

 which are armed with minute crotchets. The caudal spiracles 

 are located on the dorsal surface of the twelfth, or caudal, 

 segment. They are larger than the anterior spiracles and have 

 a distinct opening. In the living larva they, are capable of 

 being slightly extended or retracted. 



The mouth-parts have been studied from cast larval skins. 

 The external mouth-parts consist of two minute bidentate 

 mandibles, and two mouth-hooks (Fig. 8a, m. and m. h.). 

 These structures are attached on each side of the small mouth 

 opening. The internal structure consists of a pharyngeal plate 

 in the form of a shallow trough with two curved anterior arms 

 which meet and form a circular loop above the mouth cavity 

 (Fig. 8a, ph. p.). Attached to the margins of the pharyngeal 

 plate and loop is a tough membrane which forms the dorsal 



