Lake Maxinkuckee, Physical and Biological Survey 33 



ones referred to above, found near shore in sandy bottom along 

 the east shore of Long Point. Just as one species of Caddis-worm 

 builds a case resembling a snail shell, the case of these bears some 

 resemblance to a limpet, or to a marine genus of mollusks, Crepi- 

 dula, showing how similar conditions of life lead to similarity of 

 form. The caddis-case under discussion is very effectively con- 

 cealed by its resemblance to the sand on which it is found; most 

 were found while screening sand in the search for young mussels. 

 The central portion of the shell that is the first part built is 

 composed of very minute sand grains; around the margin, either 

 because the larva has become stronger and can handle coarser ma- 

 terial, or because they build up more rapidly, coarser bits are used. 

 When the builder has chosen one sort of material it appears to 

 make some effort to match it. In some cases the valves of the 

 shells of a very small bivalve mollusk, Pisidium, were used around 

 the margins and the cases thus built were especially attractive. 

 The larva lived in a little arch or compartment below the roof of 

 the case. 



ORDER COLEOPTERA 



THE BEETLES 



No special attention was given to the beetles except a few 

 species found in and about the water. No one could help noticing 

 the tiger beetles which were present in considerable swarms on 

 sandy beaches and were conspicuous on hot days, hopping or jump- 

 ing before one walking along shore. There were two kinds pres- 

 ent, a brown one and a bright, metallic green. 



Whirligig beetles, Dineutes, were common about the edges of 

 the lake. Some were seen swimming about as late as November 4. 



The Predaceous Diving Beetles (Dytiscus) were not especially 

 common in the lake. We obtained, however, an example of D. 

 hybridus. 



The water-scavenger, Hydrophilus, appeared more common in 

 pools and ponds than in the lake itself. The egg cases were com- 

 mon on the under sides of the thallus of Riccia. 



Small hemispherical or rather oval red beetles with black spots 

 (Melasoma interrupta) were exceedingly abundant on the willows 

 along shore early in the spring of 1901. The adults laid the eggs 

 on the leaves of the willows and the young which soon hatched 

 almost defoliated the trees, and the water of the lake was almost 

 covered with the adult beetles. 



The "water penny", the larva of Psephenus lecontei, was com- 

 mon under pebbles in the lake, its chiton-like form arousing con- 



3 17618 Vol. 2 



