26 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.65. 



setae on its mesal margin, maxillary palpus three segmented; ligula 

 with four fine setae arranged in a transverse row at its ventro-distal 

 end, proximal segment of labial palpus with three spinelike projec- 

 tions at its ventro-distal margin and with two setae on each side of 

 these spines, proximal segment with four setae and the distal segment 

 with one. 



Thorax. — Pronotum with the cephalo-lateral margins extending 

 almost as far cephalad as the mesal portion, lateral margins slightly 

 carinate, primary setae large, prominent and slightly flattened, sec- 

 ondary setae small, not over ten in number (fig. 54). 



Ahdonien. — Chitinized areas distinct, secondary setae short, fine 

 and not numerous (fig. 96) ; ninth abdominal sternum with the 

 caudal margin bearing two groups of four setae each ; median hooks 

 with two setae; inner hooks with two setae, the spinelike projection 

 slightly more than one-half the length of the hook (fig. 126). 



Measurements. — Length of larva, 19 to 22 mm., width at the third 

 abdominal segment, 1.8 to 2.2 mm.; diameter of ocellus 2, 0.26 to 

 0.28 mm.; distance between ocelli 1 and 2, 0.30 to 0.35 mm.; length of 

 f ronto-clypeo-labral area, 1.70 to 1.75 mm. ; width, 1.80 to 1.85 mm. ; 

 length of pronotum, 2.1 to 2.3 mm.; width, 3.1 to 3.5 mm. 



This species is very similar to C . imrpurea graminea^ but can be 

 separated from it by the larger number of secondary setae on the pro- 

 notum, and the longer length of the spinelike projection of the inner 

 hooks. 



The adults appear from hibernation later in the spring than do 

 those of G. purjjurea graminea and the eggs are laid in June. By 

 fall the larvae have reached the second instar, in which stage thej 

 pass the winter. They appear the latter part of the following Ma}' 

 or the first of June, pass into the last larval instar, and pupate in 

 July. Some of the adults emerge in August while others remain in 

 the pupal chamber until the following spring. They reach sexual 

 maturity in the spring about a month later than C. purpurea 

 graininea. The larvae are found in clay on steep banks of Lake 

 Michigan. The burrows enter at almost a right angle to the surface 

 and curve into a nearly horizontal position at the inner end. They 

 are from 7 to 10 centimeters deep and there is usually a chimney- 

 like structure around the opening of the burrow which is formed by 

 the soil excavated by the larva. Criddle (1910) states that the 

 larvae are found at Atweme, Manitoba, in situations similar to those 

 observed by Shelford, the depth of the burrow varying from 3 to 8 

 inches. The length of the larval stage is approximately 2 years 

 and the adult stage from 9 to 11 months. In the vicinity of Chicago, 

 Illinois, the larval stage lasts about 14 months and the adult stage 10 

 months. 



