74 THE entomologist's recobd. 



of high mountains to do with the question of dispersal ? In Entom. 

 Neics, viii., pp. 49-50, Piper publishes an interesting paper on the 

 massing of Hij>fodamia h'conti'i (under the name of CoccineUa trans- 

 versoguttata) on the summit of Moscow mountain, Idaho. He observes 

 on the abundance of the species at Pullman, Washington, and states 

 that, in winter, a hundred or more may be taken under a board or 

 similarly sheltered, but this habit is an entirely different one from that 

 observed in July, 1893, when, while collecting on the summit of the 

 Moscow mountain, at an altitude of 5000 feet, he 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, a 

 mass of their bodies over a foot square and two inches thick, was 

 picked up in one piece from under a flat piece of rock. It contained, 

 from estimates made later, the remains of over 10000 individuals ; 

 and 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 of them, to the observer's knowledge, are ever affected by 

 these insects in sufficient numbers to furnish food for the hosts that 

 had perished there. In October of the same year, Aldrich observed, 

 on the same peak, living ones of the same species, and the phenomenon 

 was reported to him as occurring on nearly all the neighbouring buttes, 

 one of which, indeed, is called Ladybird IMountain. 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 assembling. In 

 July, 1896, while collecting on the Blue Mountains, Washington, 

 Piper found the same ladybird on the barren rocky summit of a peak, 

 5000ft. 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. Piper says he heard them before 

 he saw them, and actually supposed that he had disturbed a nest of yel- 

 low jackets. The summit of this particular peak was quite barren and 

 could not possibly furnish food enough for the ladybirds seen. 

 Furthermore, careful search of the vicinity failed to detect a single 

 aphis or even trace of aphis work. That the phenomenon is not 

 confined to mountain peaks appears from the observation of a corres- 

 pondent 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. In view of these strange 

 facts the question naturally arises as to the significance of the habit, 

 and thus far no explanation has been proposed that will stand critical 

 examination. A common opinion is that the insects seek the rocks for 

 warmth and shelter. If this be so, why do they seek only the rocks 

 near the summit of the peaks, and not those lower down '? Again, 

 why should they seek shelter on a hot July day ? Finally, it would 

 seem that the summit of Moscow mountain furnishes them not with a 

 shelter but a graveyard. It must also be remembered that search for 

 a shelter does not for a moment explain their assembling in such 

 swarms. A second theory would explain the phenomenon as the result 

 of air-currents carrying the insects up the peak. But if this be true, 

 why are not other insects similarly affected '? Even granting this, it 

 does not explain their remaining there in perfectly calm weather. In 

 this connection, one may state, that many insects are undoubtedly 



