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



33 



hooks with two setae, the spine-like projection one-sixth the length 

 of the hook (fig. 131). 



Measurements. — Length of larva, 14 to 16 mm., width at the third 

 abdominal segment, 2 to 2.2 mm.; diameter of ocellus 2, 0.32 to 

 0.34 mm. ; distance between ocelli 1 and 2, 0.20 to 0.22 mm. ; length 

 of fronto-clypeo-labral area, 1.45 to 1.55 mm., width, 1.60 to 1.70 

 mm; length of pronotum, 1.60 to 1.70 mm., width, 2.5 to 2.7 mm. 



The life history of this species as given by Shelf ord (1908) for 

 the northern part of Illinois differs from that of all others which 

 he had observed, in that the larval stage lasts almost two years and 

 the adult stage but a month or slightly more. The eggs are laid 

 the latter part of July and the second instar is reached by autumn. 

 They pass the winter in this instar, feed the next spring and summer 

 and reach the third instar in June or July. They feed until late 

 fall, hibernate, and come out about the first of the following May. 

 The larvae pupate in June or July and the adults soon emerge, lay 

 eggs and die. The species is two brooded, adults from each brood 

 appearing in alternate years. As a result in May both second and 

 third stage larvae can be secured, in July adults, eggs, first and third 

 stage larvae, and in October second and third stage larvae. The fol- 

 lowing table gives the life history and the stages present for the 

 three most important months of the year : 



• A=adult, E=egg, l = lst instar, 2=2d instar, 3=3d instar. 



Griddle (1910) states that the life history of Cicindela lepida is 

 probably the same at Aweme, Manitoba, as at Chicago, Illinois; 

 that is, the larval stage lasts approximately twenty-two months and 

 the adult stage two months. 



The eggs are laid and the larvae live in sand which is slightly shift- 

 ing, in northern Illinois, usually near Lake Michigan, but in some 

 cases on the tops of sand dunes one-half mile from the lake. The 

 burrows are from 25 to about 40 inches deep in northern Illinois and 

 from 58 to 72 inches deep at Aweme, Manitoba. 



45554— 25— Proc.N.M. vol.60 34 



