14 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.65. 



ally mature very soon — larval life 10 months, adult life two months — one year 

 between generations. 



(c) Eggs laid in mid summer; larvae hibernate in the second stage, reach 

 the third stage early in the second summer, hibernate again, and pupate in the 

 following May; imagoes emerge in the early part of the third summer and be- 

 come sexually mature soon — larval life 21 months, adult life 2 months — two 

 years between generations. 



That the time spent in the larval stage is influenced by tempera- 

 ture, length of the summer or growing season, and possibly other 

 factors is shown by Criddle (1910) : 



It will be noticed, however, that there is a striking difference in the life 

 cycle of some of the species, observed by Professor Shelford at Chicago and 

 those noted by me at Aweme, even when the same, or a closely related form, is 

 involved, the difference being the prolongation of the larval life over a second 

 winter in Manitoba. This seemed to be such a remarkable fact, considering that 

 there are less than 600 miles of latitude between the two places, that I felt 

 almost persuaded that some mistake had been made on my part, and conse- 

 quently decided to make further investigations before publishing these notes. 

 The results have been to leave no doubt that the life cycle of species carefully 

 observed — C. manitoba, venusta, limbata, limbalis, and probably others — lasts 

 for approximately three years ; duration of larval stage 24 to 26 months, pupal 

 2 to 4 weeks, adult 10 to 12 months. 



Many of the larvae are very restricted in their habitat, occurring 

 only in particular kinds of soil and requiring a certain amount of 

 moisture. Cicindela 12-guttata^ repanda^ and hirticolUs leave their 

 burrows if the soil becomes too dry and seek new places which are 

 sufficiently moist. The female oviposits in small holes about 1 

 centimeter deep in soil which is suitable for the development of the 

 larvae. The larva, upon hatching, deepens and widens this burrow 

 and lives in it unless conditions become unfavorable for its develop- 

 ment. Before each molt the larva closes the burrow, goes to the 

 bottom, molts, and reappears again in about one week. There are 

 only three larval instars in the life cycle. When the larva is ready 

 to pupate it makes a pupal chamber or burrow, generally at one side 

 of the main burrow, in which it pupates. The depth of the larval 

 burrow, whether it is perpendicular to the surface, spiral, or slant- 

 ing, and the character of the pupal chamber, is characteristic for each 

 species. These larval habitats aid in separating many of the species. 



CLASSIFICATION 



The characters used in the classification and the descriptions of 

 the larvae were not taken from a single type specimen but are an 

 average of the number of specimens in the collection. In some cases 

 only a single larva was available; in other species there was an 

 abundance of larval material. 



