ART. 17. LARVAE OF HOLARCTIC TIGER-BEETLES HAMILTON. 7 



{P9i fig"- i^) is laterad of tlie fused labio-stipites, is more or less 

 membranous, and has two sclerites on the ventral aspect. These 

 sclerites are separated by a flexible suture. The labio-palpus Up, 

 fig. 17) is two-segmented. The proximal segment bears at its ventro- 

 distal end three prominent, pointed projections with two stout setae 

 on the outer and two on the inner margin. The distal segment is 

 about twice as long as wide and bears a single seta on its ventral 

 aspect. The ligula {li, fig. 17) is the membranous area distad of the 

 fused labio-stipites. Its ventral surface is anteriorly trilobed and 

 crossed by a transverse row of four setae about one-half way be- 

 tween the point of attachment of the palpigers and the distal end. 

 The entire dorsal or buccal surface of the labium (fig. 21) is mem- 

 branous and is covered w^ith numerous fine setae with a fringe of 

 long setae on the dorso-lateral margins. MaxiUulae or paragnathae 

 (=paraglossae) are not present. 



The thorax will be discussed under the divisions: The cervical 

 region, the prothorax, the meso- and metathorax, and the legs. 



Cervical region. — The cervical region consists mostly of mem- 

 brane. Dorsally a triangular, chitinized area, the " intertergite " 

 of Crampton, fits into tlie caudal, V-shaped margin of the head. 

 There are two narrow, dark colored, longitudinal areas near the 

 middle of this sclerite which extend entad at their caudal margin 

 as narrow, straplike projections. Laterally and ventrally an irreg- 

 ular, indistinct, chitinized area, the " inter pleirHte " of Crampton, 

 occurs on each aspect of the cervical region {ip, fig. 38). Each 

 sclerite is transversed longitudinally by a row of minute setae and 

 at the caudal margin is a small pit which is an invagination for the 

 attachment of muscles. Ventrally the cervical region is entirely 

 membranous and permits of considerable dorsal movement of the 

 head. Its caudal extent is indicated by a shallow convex furrow. 



Prothorax. — The prothorax is considerably specialized and, to- 

 gether with the head, is adapted to the larva's mode of living. The 

 pronotU'in (pn, fig. 37) is large, heavily chitinized, highly colored, 

 and shield shaped. The lateral parts of its cephalic margin are 

 emarginate and permit a close contact with the caudal part of the 

 head. The lateral angles extend cephalad as far as the meson; the 

 caudo-lateral angles are broadly rounded, and the lateral margins 

 extend upon the ventral aspect. There is a furrow along the meson 

 and a short crescent-shaped furrow on each lateral half of the 

 pronotum. The setae are short, white, slightly flattened, and ar- 

 ranged as shown in figures 37 and 54. A row or fringe of setae ex- 

 tends around the entire margin of the pronotum, becoming more 

 numerous on the caudal part. The color of the pronotum varies 



