REPORT OF THE SOCIETY 73 



grass. Within a few hours after emerging from the egg, the young larva, a 

 very active creature, spins a web on a blade of grass or in the axil between the 

 blades, and makes this its place of retreat. Later it weaves a cylindrical 

 nest of web and entangled bits of grass on the side of a grass stalk just at the 

 surface of the ground. As the insect grows it enlarges its nest and so always 

 has a place of snug retreat where it may remain hidden from marauding 

 ground-beetles and other hungry creatures. Unless sought out especially, 

 these nests escape detection and the damage done by their occupants is 

 rarely attributed to its proper source. A diligent search of a few square feet 

 of grass in any meadow, will, however, usually reveal a nest or two. The 

 larvae spend their first summer feeding when the sun is obscured, and con- 

 cealed when it is brightest. At times a larva will draw the end of a blade of 

 grass within its nest where it can eat without any fear of being picked up by 

 a passing bird and itself being made a meal for a nestling. As winter 

 approaches the caterpillars prepare for hibernation, leachellus early in August, 

 trisectus in October, and most of the other species in September. Their 

 preparation consists in extending their summer nest, a structure perhaps a 

 quarter of an inch long, a short distance beneath the surface of the ground. 

 Few of our species go more than an inch into the soil. As the time for 

 hibernation approaches they feed less and less ravenously, and finally stop 

 eating and seal the entrance to their nest with a web in which is caught 

 shreds of vegetable matter or pieces of soil. When the grass takes on a new 

 life in the spring, the larva awakens from its long winter-sleep, opens its nest 

 and begins again an active life of voracious feeding. The nest is soon en- 

 larged or a new one built, for the full-grown caterpillar of most of our' 

 Crambids is about one inch in length. As the larva reaches maturity it 

 develops an appetite which seems to be insatiable. A few days before 

 pupation, it throws caution to the winds and feeds continuously. It pupates 

 in a loose cocoon spun in a burrow just beneath the surface of the ground. 

 The period of pupation lasts from ten days to one month, depending on the 

 temperature and the species. :■..:•.: 



V • • , 



There is little apparent difference in the known larvae of our Crambids. 

 Some inay be distinguished with comparative certainty by thieir colours but 

 an absolute diagnosis is often difficult or impossible. When we consider 

 that the habits, surroundings and enemies of all our species are much alike 

 we realize that marked variations are uncalled for. Their food plants, 

 grasses and sedges, are everywhere found in abundance, hence structural 

 adaptations for change of food are unknown. An army of one species takes 

 the place of an army of a related species with each new growth throughout 

 the season. 



