56 Zoologica: N. Y. Zoological Society [HI; 3 



coccids station themselves in a row in each groove, with the long 

 axes of their bodies parallel with the long axis of the petiole. 

 Since both beetles and coccids center their feeding activities 

 on the tissue forming the floor of these grooves it is important 

 that they shall be kept clean so that the parenchyma, which is 

 continually proliferating, can be easily reached by both species 

 of insects. (Plate III, fig. 5). Hence the beetles carefully 

 deposit their feces, or frass, which has a chocolate brown color, 

 on the areas between the grooves. As time goes on the accumu- 

 lations of frass acquire the form of more or less longitudinal 

 ridges projecting into the petiolar cavity (Plate IV, figs. 2-3 and 

 Plate V) . In many petioles these ridges are strikingly regular, 

 in others more vermiculate, interrupted or anastomosing. In 

 old petioles inhabited by old colonies of Coccidotropfms the inter- 

 ior of the petiolar cavity presents the appearance of the figures 

 on Plate V. In addition to these frass ridges the beetles also 

 build a more or less circular wall of the same substance around 

 the entrance, so that the latter is converted into a short tube, in 

 which one of the beetles often stations itself on guard for 

 hours at a time, with the long axis of its body at right angles 

 to the long axis of the petiole and its flattened head exactly 

 filling the elliptical orifice. (Fig. 11). From time to time the 

 beetle may project its antennse out into the air and wave them 

 about, so .that the petiole from the outside suggests the nest 

 of one of the smaller species of Cryptocerus, with a soldier or 

 worker ant on guard at the orifice. 



The female beetle begins to lay her eggs either before or 

 after the entrance of the coccids. They are deposited singly 

 along the edges of the frass ridges and evidently at intervals of 

 several hours or even days, for dissection of the beetles shows 

 that only a few eggs mature at a time in the ovaries. They 

 are glued to the wall of the petiole rather firmly and always 

 with their long axis parallel with its long axis and that of the 

 food-grooves and frass ridges (Fig. 11). As I have not wit- 

 nessed oviposition I have been unable to determine the length 

 of the embryonic period. The eggs hatch, of course, at intervals, 

 so that the larvse vary greatly in size, some being very small 

 and evidently just hatched, others a third or half-grown or 

 actually full-grown and ready to pupate. Like the beetles, the 



