146 NOTES ON ANTHOPHORA ABRUPTA 



G. Entrance Tubes 



As already mentioned some of the burrows were evidently 

 completed on July 3, 1919. One strange feature about the 

 entrance to the burrows are the cylindrical tubes extending 

 down and outward from the entrance holes. Walsh undoubtedly 

 refers to these tubes when he writes that Anthophora abrupta 

 builds an entrance to its burrows "of tempered cloy . . . about 

 two inches long and three quarters of an inch in diameter." 

 Say, referi'ing to tne habits of the European Anthophora parie- 

 tina Latreille, says that this species digs a hole in a clay bank 

 and that the "entrance consists of a cylinder extending down- 

 wards from the mouth of the hole more than an inch in length 

 and consisting of small pellets of earth compacted together, 

 very rough on the exterior and smooth within." Certain other 

 insects are known to construct cylinders at the entrance to their 

 underground burrows. The cylinders about the orifice of each 

 tuimel at Oakwood varied from a quarter of an inch to four 

 inches in length. The inside diameter of the cylinders was 

 about one-half inch. The difference in length is probably due 

 to the fact that some of the burrows were started sooner than 

 others, though it is possible that under certain environmental 

 conditions erratic individuals may make them very short or 

 even neglect them altogether. It is to be noted that in figure 

 2 many of the holes lack an entrance cylinder, but it is probable 

 in this case that many if not all of these are simply old unin- 

 habited burrows. As in the case of Anthophora parietina the 

 tubes are very smooth on the inside, rough on the outside and 

 made of small pellets of clay removed from the inside of the 

 burrow. One peculiarity of the tubes or cylinders is an open 

 fissure on the uppermost portion, more noticeable in some 

 examples than in others. Similar "bent -over chimneys of 

 clay" were observed by Nininger, and also by Kellogg, over the 

 entrances to the burrows of Anthophora stanfordiana. Entechnia 

 taurea likewise makes such an entrance chixnney over the burrows 

 according to Say, who says "many of the tubes . . . . , have 

 a fissure above, throughout the whole length." Riley reports 

 finding these odd-looking chimneys extending from the entrance 

 of the burrows of Anthophora abrupta, and has theorized con- 

 cerning their purpose. This writer has suggested that these 



