WERNER MARCHAND 19 



cylindric, slender, tapering at both ends, capable of contraction and 

 extension, their body consisting of a head and twelve segments, the 

 last segment being very short. The larvae are eucephalous, with head 

 well developed but small, bearing the three-jointed antennae, at- 

 tached to the anterior angles of the head just above the palpi, the 

 basal joint being short, the others of varying length. A bunch of 

 stiff spines, either short or moderately long, is situated above each 

 antenna and on each side of the labrum. All the essential mouth- 

 parts are present and have been studied in many species. They are 

 well adapted for seizing the prey, and constitute a very formidable 

 apparatus (Patton and Cragg). The essential organs are the man- 

 dibles and first maxillae, and of these the former are the most powerful 

 weapons. Each mandible is a stout rod of chitin, slightly expanded 

 at the base, to which the muscles are attached, and narrowed distally 

 to a blunt point; the rod is curved downwards and forward, and on 

 its concave border has many coarse serrations. The maxillae are 

 similar in shape and general disposition, but are smaller and less 

 hea\dly pigmented, and are more pointed. Both pairs of appendages 

 can be thrust out from the head in a downwards and forward direc- 

 tion when the larva attacks its prey, by means of the protractor and 

 retractor muscles attached to the base of the rods. One sometimes 

 becomes aware of the existence of these organs when handling the 

 Iarv£e, as they are used in defense as well as in attack, and are cap- 

 able of inflicting a sharp nip, though they do not draw blood. The 

 maxillary palpi are simple and two-jointed, the distal joint being 

 much smaller than the proximal one. The dorsal and distal ex- 

 tremity of the head is projected forward as a short and fleshy labrum. 

 A labium is likewise present. The head is attached firmly to the 

 pharynx, and is retracted and exserted together with it. The pharynx 

 itself is an elongate chamber of the usual type and is easily seen in 

 the living larva. The eye-spots are placed on the dorsal side of 

 the pharynx, not on the outer cuticle, and follow the movements 

 of the pharynx. The pharynx leads posteriorly to the esophagus, 

 which is narrow, but wider and more muscular than that of the adults 

 It is usual to find that the esophagus is wider and more muscular in 

 insects whose food is solid or semisolid than in those which take only 

 fluid food. 



