316 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



approach to rapidity of movement observed during the summer was in the case of a 

 single individual suddenly surprised by the morning sun while at a distance from a 

 suitable hiding-place which he was making frantic exertions to discover. 



In a brief paper contributed to this Academy by Mr. H. A. Brous, at our last annual 

 meeting, it was stated that Arriblychilos live in holes which they construct for them- 

 selves. My own observations do not corroborate this statement. On the other hand, 

 I found them invariably coming forth at night from holes made by other animals, most 

 especially from the intricately winding burrows of the kangaroo rat {Di^odomys jpMl- 

 lippii), by which the clay banks are often completely honey-combed. In these bur- 

 rows they take refuge from the direct rays of the sun in the daytime, in company with 

 other nocturnal genera — Eleodes, Pasimachus^ &c. These latter insects undoubtedly 

 furnish many a midday meal for AmbJycMlce, which are not to be supposed to pass the 

 entire day in sleep. On one occasion I had an opportunity of watching two of them 

 in a large abandoned badger's hole. They were wide awake, and walking about with 

 vibrating antennae, as if in search of food. I have also kept several living specimens 

 in confinement, and have carefully watched them for several weeks, but never discov- 

 ered any disposition to make excavations for themselves, though they would gladly 

 take possession of holes made for them in the earth at the bottom of the cage. 



In regard to food, no living insect seems to come amiss to them. They seem to be 

 especially fond of all sorts of Orthopterous and Lepidopterous larvae. They will attack 

 and devour the huge wingless locusts (Bracliypeplus) and sword-bearers (Ensicaudes). 

 I have seen them in the act of conquering and devouring the large Frionus of the plains 

 {P. fissicornis), and in two instances have seen them eating one another, apparently 

 with the keenest relish. In confinement they will thrive upon full-grown maple- 

 worms (Dryocampa rubicunda var. alba), the caterpillars of the Handmaid Moth {Da- 

 tana ministra), and almost every other insect pest of the orchard and garden. 



We have ourselves kept a liviug specimen, sent us by Professor Snow, 



in a vivarium all through the 

 past autumn and winter. It 

 showed an admirable capacity 

 for burrowing, and doubtless ex- 

 cavates its own burrows where 

 those of other animals are not 

 at hand to occupy. Our speci- 

 men devoured at first at the rate 

 of two locusts a day, but subse- 

 quently became much less raven- 

 ous. It ate at night when the 

 locusts were least active, and 

 generally remained quiet and 

 hidden in its burrow during the 

 day. 



The larva (Fig. 53) of this spe- 

 cies lives in a large cylindrical 

 hole, from one to three feet deep, 



riG.53.-AMBLycHiLACYLiNDRiFOBMis.-a,iarTa,iat- made in dry clayey banks; and 



eralview; &, same, dorsal view: c, head, prothorax, tit., "o ttt n-nil/l in n Ipffpr fn 



and mesothorax; (Z, antenna; e, bead beneath; /, men- ^''^r. Hi. VV . VaUllU, m d leiLtrx tu 



turn and maxilla; g, leg; h, hook-bearing hump of jjj, Q. g^ Hom. of PhiladelDhia, 



joint 8. (After Horn.) -i^ . ^ , i. 7 



thus describes its habits: 



The burrows are found in all gradations of surface, from a perfect level to a nearly 

 vertical face, but are in greatest numbers in slopes of about 30^. They are very notice- 



