LARVAL HABITS OF THE TIGER BEETLES. 167 



Bombyliidse (Diptera). The holes o£ this species vary from 25 to 45 cm. in 

 depth. 



The imagoes undergo a series of colour-changes continuing to death. 



CiCINDELA HIRTICOLLIS. 



This species reaches sexual maturity in July and deposits eggs in the level? 

 white, wet sand of the beach of Lake Michigan. The third larval stage is 

 reached by most individuals in the latter part of August and the early part of 

 September. The larvse live in straight, vertical burrows, 15 to 20 cm. in 

 depth. They disappear very late in the fall (being found as late as the 

 middle of October) and reappear in April, After storms they have been found 

 crawling on the beach and after heavy rains have been found on the tops of 

 sand dunes. This is due to the fact that they leave their burrows with every 

 deviation from the optimum conditions. This makes them difficult to rear. 

 They go into the prepupal stage from the first of June to the latter part of 

 July, or even later. 



The colour of the imagoes undergoes a series of changes ; the insects come 

 out of the soil before the changes are ended and the chitin hardened. This 

 appearance begins in the second week of July while the hibernated ndividuals 

 are still present ; the beach then swarms with them. The old individuals 

 gradually disappear as the number of new ones increases, so that the presence 

 of the new brood cannot be noted by numbers. 



The number continues about the same during the month of July, after which 

 it gradually decreases. Individuals that can be recognized as fresh by the 

 condition of their cuticula have been repeatedly brought into the vivarium. 

 They soon go into the ground and do not come out. Repeated examination 

 of the females at this time of the year has never shown a single one to contain 

 eggs, nor have I seen any cases of copulation. While I have not succeeded in 

 bringing any of these individuals through the winter, there is little doubt from 

 these observations that the adults go into hibernation in two or three weeks 

 after their emergence and remain there until the following June, 



C. SEXGUTTATA. 



The female lays the eggs (June or early July) in shaded sand or clay containing 

 humus, more rarely in pure humus. The eggs are of a bright cream-yellow, 

 1-8 mm. long and 1 mm. in diameter. Most of the larvse pass the winter in the 

 last stage, a small number in the second stage. The only specimens that were 

 reared went into the prepupal stage before the 15th of June (one year after the 

 eggs were laid) and one was observed to pupate July 29th, six weeks after, and 

 emerge August 7th. All that were observed went into the prepupal stage from 

 June 11th to the 17th and all emerged between August 4th and 8th. None 

 of them dug their way out, but were removed for examination. 



13 * 



