386 The University Science Bulletin. 



have experienced personally and through correspondence; many of 

 the people engaged in the manufacture of horse collars are not aware 

 of the value of clean-threshed straw, the seed of which forms an 

 abundant food supply for these insects, and thus follows the dilemma 

 caused by the infestation. Applicable to such cases, I have per- 

 formed a series of experiments to demonstrate their relative value 

 concerning the means of extermination. Experiments were carried 

 on with heat and cold temperatures and carbon disulphide and 

 hydrocyanic-acid gases, and in conclusion I feel at liberty to state 

 that heat is to be preferred as the best means of control. It insures 

 extermination, and is by far the most economical as well as the 

 safest means of eradicating the infestations. 



With reference to the matter of multiplicity and distribution of 

 this species of insect, it was found to be a rare species generally 

 distributed over the the United States and Europe, and is omniv- 

 orous in its feeding habits. I found this species to thrive and de- 

 velop much more rapidly upon seeds and grain foods than any other 

 available material which I had at hand for testing out the food 

 habits. 



In making a summary of the variations of the life history of a 

 number of individuals of the same generation, I noted: 



1. The adults oviposit from four to six days after emergence. 



2. The number of eggs laid by different individuals varied from 

 ten to forty-five. 



3. The eggs hatch in from eiglit to twelve days at ordinary room 

 temperature. 



4. The larval life lasts about five months, on the average. 



5. The time of pupation is from ten to fourteen days. 



6. The adult lives from eight to twenty-five days. 



BIBLIOGRAPHY. 



F. H. Chittenden. 1893. — Herbiverous Habits of Certain Dermestids. Bull. 



2, N. S. Div. Ent., U. S. Dept. Agr., i)p. 36. 37. - 

 1897. — Granivorous and Other Habits of Certain Dermestids. Bull. 8 N. S. 



Div. Ent. U. S., pp. 14-24. fig. 1. 

 L. O. Howard. Extract from Corres. Bull. 44, Div. Ent, U. S. Dept. Agr., Apr., 



pp. 90-99. 

 H. F. Jayne. 1882. Revision of the Derm, of the U. S. Proc. Amer. Philos. 



Soc, vol. XX. 

 C. V. Riley. 1883.—Trugoderma as a Museum Pest. Amer. Nat., vol. 17 



p. 199. 

 1S83. — Number of Molts and Length of Lar\-al liife as Influenced by Food. 



Amer. Nat., vol. 17, pp. 347-548. 



