1920.] 1,-1 



fully developed, hut which had died within the puparium, as happened 

 also with the beetles found bj' Mr. Lyle in puparia of Ort/gmn. 



Habits of the adult Aleochara algahum.— T\\q beetles came 

 out of the puparia by gnawing an irregularly shaped hole with jagged 

 edges in its wall. The hole is usually on the dorsal side of the puparium 

 and in the front half : this is so in about 68 puparia. The remaining 

 ])uparia from which the parasites emerged number 32, and among these 

 the hole is ventral and anterior in 19 cases, dorsal and at about the 

 middle of the length in 6, dorsal and posterior in 3, ventral and posterior 

 in 1, lateral and at about the middle of the length in 2, lateral and 

 posterior in 1. The predominance of the dorsal and anterior position 

 perhaps indicates that the larva of the beetle, when inside the puparium, 

 has the same habits as that of A. bilineata, which passes the greater 

 part of its existence on the anterior and dorsal surface of the fly- 

 nymph. 



Though each Ijreeding-vessel contained many puparia, yet the 

 number of beetles was checked as carefully as possible against 

 the number of puparia showing emergence-holes, and there was no 

 evidence of more than one AJeoclim'ci ever emerging from a single 

 puparium. The beetles were extremely active, and, whenever observed, 

 most were running ceaselessly over the surface of the sand. Only those 

 in burrows, or clustering under pieces of food, were still. Occasionally 

 the}^ climbed the glass sides of the vessels to a height of 1| inches or 

 more. In several ways their habits resembled those of A. bilineata as 

 described by Wadsworth. They burrow readily and are to some extent 

 gregarious. Burrowing commenced soon after the first examples 

 emerged from the puparia. The excavations were usually little pits in 

 the sand, against the glass sides of the jars. In these hollows the 

 beetles were seen in twos, or in little groups of from 3 to 6, resting 

 head downwai'ds, with heads close together and abdomens curved over 

 dorsally. In these groups the insects are sometimes clustered closely 

 together, heads almost touching at the bottom of the pit, tails curved over 

 their backs and nearly meeting at the top. More rarely they excavated 

 narrow galleries to a depth of about half an inch : in one of these, three 

 beetles were seen resting head downwards, each close behind the other. 



As to food, Wadsworth found that allults of A. bilineata rapidly 

 attacked living maggots of the host-fly, and occasionally broke open 

 puparia and devoured their contents when no other food was present. 

 My Aleocharae did not appear to touch the puparia (most of which 

 were occupied by other members of their owai species not yet emerged), 

 and I had no opportunity to test their inclinations with regard to any 



