ABT. 17. LAEVAE OF HOLARCTIG TIGER-BEETLES HAMILTON. 57 



fronto-clypeo-labral area, 1.45 to 1.55 mm.; width, 1.45 to 1.55 mm.; 

 length of pronotmn, 1.5 to 1.6 mm.; width, 2.4 to 2.6 mm. 



The larvae were collected at Wray, Colorado, in bare, white sand 

 blowouts. The burrows were straight or slightly spiral, from 10 to 

 14 inches deep, and occurred in clusters of a dozen or more to the 

 square foot. The larvae of Cicindela lepida were dug from the same 

 situations. 



Griddle (1907) states that the larvae occur in large, sandy blow- 

 outs with scant vegetation. They are also sometimes found in small 

 patches of shifting soil but are always much more plentiful in white 

 sand, which is constantly drifting. The depth of the burrows 

 varied from 7 to 17 inches. The life cycle requires 3 years at 

 Aweme, Manitoba, approximately 2 years are required for the 

 larval stage and 1 year for the adult stage. He also writes that 

 the larvae are able to withstand much more cold than the adults, the 

 larvae remaining out until the latter part of October. 



2. Genus TETRACHA Hope. 



Head with the ridge on caudal part of frons transverse and con- 

 tinuous with the ridge on the caudal part of the vertex; latero- 

 clypeus distinct, crescent-shaped; anterior margin of labrum smooth; 

 ocelli 1 and 2 subequal in size; ocelli 3 and 4 not adjacent; ocelli 5 

 and 6 present; antenna separated from the mandible by a narrow, 

 transverse, chitinized bar, the second segment not longer than the 

 other segments combined; maxilla with the ventral sclerite of the 

 cardo triangular and bearing one large and one small seta; lacinia 

 apparently absent ; maxillary palpus three-segmented, the proximal 

 segment the shortest, the second and distal segments subequal in 

 length, the proximal segment with a spine on the latero-distal end ; 

 labio-stipites concave and with a prominent carina on the lateral 

 and caudal margins; ligula not chitinized on the ventral aspect; 

 palpiger area membranous and without chitinized sclerites; labial 

 palpus with the proximal segment shorter than the distal segment 

 and without spinelike projections on its ventro-distal end, the proxi- 

 mal segment with 6 to 8 setae and the distal segment with 1 ; fifth 

 abdominal segment with the inner and median hooks present, the 

 lateral hooks wanting, median hooks straight, thornlike, and bearing 

 1 or 2 stout setae ; inner hooks similar in shape to the median hooks, 

 about one-half their length, and bearing 2 fine, inconspicuous setae. 

 Legs with distinct, movable tarsal claws. 



This genus is represented by two species from the United States, 



both of which occur in the southern and southeastern part, and one 



species from Europe. In many respects the larvae are very closely 



related to those of the genus Cicindela. They can be separated from 



45554— 2.5— Proc.N.M.vol.65 35 



