THE INTEREST IN INSECTS 



373 



greater tenacity than is here recorded. 



It will not be ont of place here to 

 mention how the starvation experi- 

 ments with this particular species 

 which proved to be of such unusual in- 

 terest came about. While a graduate 

 student at the University of Wiscon- 

 sin the writer got into a dispute con- 

 cerning the classification of the larvae. 

 To prove his point he decided to grow- 

 some of the specimens to maturity and 

 thus obliterate the uncertainty of iden- 

 tification. A number of the largest 

 larvae available were placed in glass 

 dishes together with some food mater- 

 ial. Not having plenty of the favorite 

 food material at hand at the time, sev- 

 eral specimens were placed in other 

 dishes without food and set aside in a 

 separate drawer with the intention of 

 providing for them later. However, 

 these were neglected until the opening 

 of school the following September 

 when the writer accidently discovered 

 them in their secluded place. Much to 

 his surprise all of the specimens were 

 alive, in spite of the fact that they had 

 remained there for five months without 

 a thing to eat. It was also noticed that 

 the larvae had decreased in size. This 

 observation was further substantiated 

 by the gradual decrease in size of the 

 various cast-off skins, which this 

 species is not known to attack. This 

 interesting information later led to ex- 

 perimental work on the longevity of 

 the larvae, without food, on a large 

 scale. 



A number of specimens varying in 

 size from newly hatched to practically 

 full-grown larvae were placed in in- 

 dividual sterilized vials for the purpose 

 of ascertaining the period of time that 

 they could live without food. Even the 

 newly hatched specimens showed an 

 amazing tenacity by living over four 

 months without ever having eaten at 

 all. Some of the one-fourth grown 

 specimens lived for fourteen months ; 

 those about one-half grown lived al- 

 most three years ; those three-fourths 

 grown lived four years; and most of 

 the largest specimens lived over four 

 years, several of them over four and a 

 half years, and one five years and 

 seven days ; while the last one died after 

 five years, one month and twenty-nine 

 days of starvation. 



One of the most interesting phases 



of these experiments is the gradual de- 

 crease in size of the individual speci- 

 mens. Many of the largest larvae 

 which were about 8 mm. in length 

 dwindled down to practically the hatch- 

 ing length of I mm. before dying, and 

 practically all of the specimens which 

 were below 7 mm. at the beginning of 

 the experiment dwindled down to the 



CAST SKINS OF FASTING LARVAE. 



same dimensions. Many of the larvae 

 of 2 and 3 mm. were reduced to some- 

 what below the hatching length, and 

 practically all of the newly hatched 

 specimens fell down to about three- 

 fourths of their original length. Speak- 

 ing in terms of reduction in size, it is 

 astonishing to note that some of the 

 largest larvae have been reduced to 

 about 1/600 of their maximum larval 

 mass. 



Another, and even more interesting 

 phenomenon, is the fact that when the 

 starved specimens almost reach the 

 smallest size possible and are then 

 given plenty of food, they will again 

 begin growing in size. A number of 

 the larvae which were half grown 

 when placed under starvation for the 

 first time, have through alternating 

 periods of "feasting and fasting" at- 

 tained that size three times and are 

 now on the way to their fourth "child- 

 hood" ; and even some of the large 

 specimens have started dwindling down 

 to their third "childhood" after having 

 twice attained the practically maxi- 

 mum larval size. 



Occasionally these larvae are found 

 in large numbers in insect, seed and 

 drug collections, and naturally destroy- 

 ed as soon as discovered. The writer 



