THE INSECT WORLD. 



227 



and other flowers are injured by a black species with gray- edged 

 elytra, Epicauta cinerea, and among field-crops beets are, after 

 potatoes, the chief sufiferers. The beetles appear quite suddenly 

 in large numbers, and some species disappear almost as quickly, 

 while others linger several days. A uniformly black form, 

 Epicauta pen7isylvanica, is often found in considerable numbers 

 on the flowers of the golden-rod in August and September, while 

 a uniformly gray species, Macrobasis unicolor. is common on the 

 false indigo. 



The life history is interesting, and the species may be divided 

 into two series, those living in the nests of burrowing bees and 

 those living in grasshopper eggs. In the first series the eggs are 

 laid on flowers, and from each hatches an active little creature 

 with long legs, prominent jaws, and large head, which is known 

 as a " triungulin." It runs about the flowers until the proper 

 kind of bee comes along, gains a foothold on this, and, buried 

 among the hairy clothing, allows itself to be transported to the 

 bee nest. There it quits its unconscious host, makes its way 

 into one of the completed cells, devours first the egg or young 

 larva, and then completes its own transformations, feeding upon 

 the stores now without another owner. This type is only 

 indirectly of economic interest, but is rather injurious than 

 otherwise. 



In the second series the egg is laid either on a plant or on 

 the ground, but in either case a triungulin similar to that above 

 described results, and this has the power of existing without food 

 for several days, while hunting for a grasshopper egg-pod. When 

 such a one is found its wanderings are over, and it begins feed- 

 ing at once. When it moults its large head and long legs disap- 

 pear, and it resembles a Carabid larva, with ovate body, small 

 head and jaws, and short legs; it is now in the " carabidoid" 

 stage. Again it moults, and now the resemblance is to a 

 small "white grub," for which reason this has been termed 

 * the " scarabidoid" stage. When all the grasshopper eggs are 

 devoured, our larva is full grown, ceases feeding, and shrinks 

 into its own hardened skin, forming a coarctate stage, or 

 pseudopupa, in which it winters. In spring it emerges from this 

 covering, is active a short time without feeding, and then enters 

 the true pupal stage, in which it resembles other Coleoptera. In 



