ART. 17. LARVAE OF HOLARCTIC TIGER-BEETLES HAMILTON. 9 



long and prominent to short and inconspicuous. They are arranged 

 as shown in figure 37. 



The meso- and meta-thoracic pleura (figs. 1 and 37), except for 

 size, are similar in form and development. The coxal process {cxp, 

 fig. '37) is black and heavily chitinized. The pleural suture (pis, 

 fig. 37) extends dorso-cephalad from each coxal process and sepa- 

 rates the pre-hypopleurite from the post-hypoplcurite. Each post- 

 hypopleurite bears five or six setae on its caudal part. Tlie ento- 

 pleurum is invaginated along the pleural suture. The epipleurum 

 {epl, fig. 37) has a small, chitinized spot, bearing one to a few setae, 

 caudad of the post-hypopleurite. 



The spiracle (fig. 1) of the mesothorax is annular, large, brown, 

 elliptical, and is on the lateral aspect in the intersegmental membrane 

 between the mesothorax and prothorax. This spiracle is about twice 

 the size of the spiracle on the first abdominal segment and three 

 times the size of the remaining abdominal spiracles. There is no 

 spiracle on the prothorax and only a rudimentary one on the meta- 



thorax. 



Between the prothorax and mesothorax and the mesothorax and 

 metathorax are the intersegmental folds (if, fig. 38). These folds 

 are entirely membranous. 



The sterna of the mesothorax and the metathorax are largely 

 membranous. The mesosternum consists of presternum, eusternum, 

 sternellum, and poststernellum, while in the metastemum the pos- 

 ternellum is absent. Each presternum {pst, fig. 38) has on its 

 lateral side a small, chitinized spot bearing a single seta, and each 

 eu^ternu7n {eust, fig. 38) has a larger, median, chitinized spot bear- 

 ing four setae. Caudo-mesad of each leg are the small pits which 

 mark the invagination for the furcae (fu, fig. 38), and behind these 

 we have sternellum posteriorly reaching to the invaginations for 

 furcellae. The poststernellum with spiTia is only present on the 

 mesothorax and is entirely membranous. An eversible structure 

 (fig. 38) , probably a gland, is located on the meson of the presternum 

 of the metathorax. 



Legs.—i:\\Q legs of the prothorax, mesothorax, and metathorax are 

 very similar and can conveniently be described together. The length 

 of the legs increases gradually, but slightly posteriorly. The coxa 

 {ex, fig. 33) is almost as long as the remaining segments of the leg, 

 subcylindrical, and articulates at its proximal end by a dark and 

 heavily chitinized acetabulum to the coxal process of the hypo- 

 pleurum. The trochantin {tm, fig. 33) is separated from the proxi- 

 mal end of the coxa by a shallow furrow. The trochantin and 

 the furrow which separates it from the coxa are more pronounced 

 and larger in each of the following pairs of legs. The trochanter 



