146 The University Science Bulletin. 



would get on but a few hours together. The sand was moistened 

 each day, and the jars covered with ground-glass covers. Each 

 nymph was examined daily for molts, which were removed and 

 placed in vials of alcohol or on cotton in small tin boxes, and each 

 instar skin of each insect reared was preserved separately for study. 

 This has provided adequate material for study of structural details 

 of each stage. 



We endeavored to determine whether the insects had any choice 

 of soil, by placing them in pans containing sand on one side and 

 sandy loam on the other. Our results were not conclusive. We 

 also used sterilized sandy loam in some of the rearing jars instead 

 of the sand and found it of no advantage. 



The insects were fed house flies, plant lice, oscinid flies, cicadellids 

 and many other small insects taken in sweeping the grass upon the 

 campus. Each day the dead carcasses were cleaned out of the rear- 

 ing jars and freshly killed insects inserted. 



Mortality was very high, as a glance at the tables presented be- 

 low will show, and indicates that some essential factor of their 

 natural habitat was lacking. The fact that 116 nymphs out of 179 

 died in the first stage, and that they usually succumbed on the 

 date when molting might have been expected to occur, would point 

 to a hazard of ecdysis. An examination of the dates of death of 

 the older nymphs further substantiates this view. 



Toward the end of a stadium the nymph always appears plump 

 instead of flat, and so the appearance of the nymph indicates ap- 

 proximately its development. Thus some would become plump in 

 a week and molt; others would develop more slowly. 



In spite of the discouragements because of the very high rate of 

 mortality, the tending and study of the rearings were very interest- 

 ing. Mr. William Hoffman, who assisted me very materially dur- 

 ing the latter part of the summer, found the task most absorbing. 

 He fed the nymphs and kept the records with as much interest, 

 care and ingenuity as I could have done, and I desire to acknowledge 

 herewith my indebtedness to him for his services. 



HABITAT. 



The toad bug is a shore bug, found along the muddy banks of 

 small streams or the sandy beaches by the river. It is a notable 

 example of protective coloration. Specimens taken on muddy banks 

 are dull and slaty grey with indistinct pattern, while those from 

 the sandy beaches are variegated, pebbled and mottled like the 

 sand. Specimens in captivity have been observed to burrow be- 



