50 ENTOMOLOGICAL NEWS. [March, 



similarly sheltered. But this habit of sembling when seeking 

 shelter seems to be a totally different thing from the one now to 

 be described. 



In July, 1893, while collecting on the summit of Moscow 

 Mountain, Idaho, altitude about 5000 feet, I was astonished to 

 find in the crevices of rock near the summit immense numbers 

 of dead ladybirds of this species. As an illustration of their 

 great numbers I may mention that under a flat piece of rock I 

 picked up one mass of their bodies over a foot square and two 

 inches thick. It contained, from estimates made later, the re- 

 mains of over ten thousand individuals. A careful search of the 

 vicinity failed to disclose any living ones. None of the plants in 

 the vicinity were infected with scales or aphides, and none ot 

 them to my knowledge are ever affected by these insects in suffi- 

 cient numbers to furnish food for the hosts that had perished there. 



In October of the same year Prof. J. M. Aldrich observed, on 

 the same peak, living ones of the same species, and the phe- 

 nomenon was reported to him as occurring on nearly all the 

 neighboring buttes, one of which, indeed, is called Ladybird 

 Mountain. 



Prof. Aldrich states that the beetles were so abundant that he 

 could gather them by the handful, but that he could detect no 

 reason for their sembling. 



In July of the present year while collecting in the Blue Moun- 

 tains, Washington, I found the same ladybird on the barren 

 rocky summit of a peak, 5000 feet high. The insects were 

 crawling over the hot, bare rock, and upon being disturbed 

 would circle about for a few moments and again alight. So great 

 were their numbers that they made quite as much noise as a small 

 swarm of bees. Indeed, I heard them before I saw them, and 

 actually supposed I had disturbed a nest of yellow jackets. 



The summit of this particular peak was quite barren and could 

 not possibly furnish food enough for the ladybirds I saw. Further- 

 more, careful search of the vicinity failed to detect a single aphis, 

 or even traces of aphis work. 



That the phenomenon is not confined to mountain peaks ap- 

 pears from the observation of a correspondent in Kittitas County, 

 Washington, who reports a ladybird, in all probability the species 

 under consideration, as gathering in great numbers about a large 

 boulder near his house. 



