August, '14] GOODWIN: HEAT CONTROL FOR MILL INSECTS 317 



or daj'S after the test. While it may not be killed outright by the 

 heat, certain of its tissues, or organs, seem to become fixed, failing to 

 perform their normal functions, and this causes death some time after 

 the actual treatment. 



Cathartus gemellatus, a closely related species, seemed to be affected 

 similarly by heat; the fatal or killing temperature being the same, and 

 the final results very nearly the same. 



Lcemophloeus minutus. These tiny beetles are hard to kill, almost 

 50° C. being necessary. The larvse and pupae were killed by 48° C. to 

 49° C, and no eggs hatched after being treated to 45° C. These small 

 beetles are among the most difficult of the Cucujidce to kill with high 

 temperature, but almost no difference could be detected between the 

 effects of moist and dry heat, the average difference in effective temper- 

 ature being less than .25 or I of a degree Centigrade. They commonly 

 occur in flour, corn meal, cereal products, nuts, raisins and sometimes 

 in dried fruits. They are so small and flat that they easily find en- 

 trance beneath the lids of all but the closest fitting canister tops, and 

 thousands of individuals will often be found in a few ounces of food 

 material. Several scores of individuals were found living in a chest- 

 nut from which the larvae of Balininoe had emerged. 



Trogoderma ornatum. The young larva of this Dermestid survived 

 most of the tests, being seemingly much better fitted to resist extremel}^ 

 high temperatures than the other stages of this insect. It is much 

 more resistant than any other of the species of cereal pests, as far as 

 these have been tested by the author. The young larvae become 

 very active at 45° C. to 47° C. and continue their activities with irreg- 

 ular periods of inactivity until a temperature of 52° C. to 53° C. is 

 attained. At 52° C. the young larvae begin dying and usually are all 

 dead before a temperature of 53° C. is attained. The beetles, pupae 

 and full grown larvae were readily killed by 48° C. to 50° C. Moist 

 atmosphere at 48° C. to 50° C. was fatal to the beetles, pupae and full 

 grown larvae, but was no more effective than a dry atmosphere at 

 similar temperatures. This species will subsist on corn meal, popcorn, 

 sweet corn, nuts, feathers, skins, museum specimens of birds, mammals, 

 insects, etc., furs, woolens, and is almost a universal feeder. 



Sitodrepa panicea. The drugstore beetle is readily killed in all 

 stages by 47° C. to 49° C, there being apparenth' no difference between 

 the effect of a heated moist or a heated dry atmosphere. This beetle 

 is of special importance as it is truly a universal feeder on dried herbs, 

 roots, grains, cereal products, and drugs of many kinds. It is a pest of 

 the herbarium and museum, besides being a common drugstore pest. 

 It may eat leather, if no other food is present, and it has, in a few 

 instances, almost destroyed horn scoops in boxes of drugs where the 



