84 



THE REPORT OF THE 



[ No. 19 



A very valuable contribution to our literature upon these insects will be found in 

 Bulletin 23, Agricultural Experiment Station, Cornell University, pages 120-24, by Pro- 

 fessor Slingerland. The two forms are so exceedingly alike in appearance that none bat 

 expert entomologists have been able to separate them. As relating to this matter Mr. F. 

 H. Ohittenden, Assistant Eutomologist in the Department of Agriculture, wrote me Feb. 

 8bh, 1899, also stating that he had been unable to avoid the impression that the two in- 

 sects were distinct, notwithstanding the opinion of specialists to the contrary. I speak of 

 this more in the way of a suggestion, as it seemed to me a problem which a careful ent> 

 mological student may well take up and solve, 



HABITS OF THE LARV^ OF DERMESTES TALPINUS (MANN.) 



By Percy B. Gregson, Waghorn, Alberta, 



To fur trappers in the far North West the larva of this beetle, which Dr. Fletcher has 

 kindly identified for me, is but too well known. (Fig. 46.) It seems to be ubiquitous 

 and almost omnivorous. Hitherto, however, it has been understood to feed only on 



dead things, such as fur hide, skin, bacon, wool, dead insects, 

 etc., but in rearing it, as I have in considerable numbers, I 

 have noticed features which show the larva in its very early 

 infancy to be endowed with a very extraordinary activity, or 

 to be a parasite of living insects. These features I should like 

 now to record. 



My practice when spreading lepidoptera is to place the 

 setting boards within a box with closely- fitting door, but the 

 frequent destruction of the insect by the Talpinus larva, 

 before the insect itself had become sufficiently set for 

 removing, determined me to investigate the early existence of 

 the larva. I noticed that the butterflies I caught in May and 

 early June (Colias occidentalis, E. discoidalis, etc.) were 

 peculiarly liable to attacks by thia pest. Others caught later 

 m the year were free from them. When I discovered the 

 larva on the setting boards (generally on the second or third 

 day after setting the insect) the largest of the larvae did not 

 exceed one line in length, and from the dust-like frass under 

 the body of the butterfly and the excavation made in the body, 

 the larva had evidently been at work for some time. It being 

 easily possible for such minute creatures to have crept through 

 fome small crack into the interior of the box, I decided this year (1900) to rear a few, 

 as soon as I could get any, in a tightly closed tin tobacco box three inches deep, for I 

 found they could not crawl up the tin sides of such a box. They cannot crawl up tin at any 

 slope greater than 30 degrees. Placed on the higher part of such a slope, they slide down 

 to the bottom. 



On the 12th of May, 1900, I found a Z>. talpinus larva on a hybernated speci- 

 men of Vanessa cardui which I had captured and spread on the 10th. This little larva 

 (not a line in length) I at once placed in the empty tin tobacco box, with the carcase of 

 the V. cardui, and closed the lid and saw that th«re wag no space for ingress of even the 

 minutest insect, assuming that it first could scale the tin sides of the box. Being much 

 occupied for the next few days, I simply added a Colias or two (caught in the manner I 

 shall presently describe) without disturbing the little grub which was within the carcase 

 cf the V. cardui. On the 25 th May I introduced to him a Colias occidentalis caught 

 that morning. I always carry with me when hunting near home for lepidoptera, a 

 shallow (^ inch deep) tin cigarette box whose lid fits very tightly, requiring an efibrt in 

 fact to open, and into this box I at once place, direct from the net, my captured speci- 

 mens, folding them in papers on the spot (first, however, killing the Colias, Erebias and 

 such sized insects by pressure on the thorax in the net) and it is therefore impossible for 



Fig. 46 represents the 

 beetle and larva (magnified) 

 of Deronestc.t lar-darius — a 

 most familiar species. 



