PAMMEL — POLLINATION OF PHLOMIS TUBER05A. 253 



in a longitudinal direction, the tissue yields easily, so that longi- 

 tudinal slits are the result. At other times the mandibles are 

 drawn backward and forward, thus causing longitudinal slits. 

 The number of slits varied from one to three. The insect did not 

 take much trouble to find the old slits, but went directly at mak- 

 ing new ones, as it seemed to be easier for it to do this than to 

 waste time in looking for the old ones. 



Wasps also perforate flowers, especially such as are adapted to 

 this class of insects. Prof Trelease found that the flowers of Scro- 

 phularia nodosa^ var. Marylandica (114) are perforated by the 

 White-faced Hornet, Vespa maculata; he also found that Ribes Cy- 

 nosbati (i 13) is perforated by the same species. Miiller (82 a) 

 found a species of Odynerus perforating the flowers of Symphori- 

 carpus raceniosus, which Prof, Trelease (113 & 1 14) has also found 

 perfoiated in this country. Mr. Robertson has reported to me 

 several interesting- cases where wasps use perforations, and, at 

 least in one instance, make them. At Orlando, Fla., he found five 

 species of wasps belonging to the genera Poiistes, Eumenes, and 

 Odynerus, which sucked the flowers of Gaylussacia dximosa, var. 

 hirtelia,* through perforations (Fig. 6 a, PI. vii.), which are at first 

 very small, but finally large and irregular. At Clinton, Mo., he 

 observed that Odynerus foraminatus made perforations in the tube 

 of the corolla of Monarda Bradburiuna,-\ which, as he thinks, 

 were made by the wasp taking the tube between her jaws and 

 cutting towards the mouth of the corolla, thus loosening a tri- 

 angular piece which could be closed over the opening (Fig. 9 a, 

 Plate VII.) In the Botanic Garden I frequently found the flow- 

 ers of this species perforated, but the perforations were in the form 

 of longitudinal slits. 



While wasps do not generally perforate flowers, they are not 

 above using those perforated by species of Bombus and other 

 insects ; for these, in their rapid visits to flowers, are certain to 

 leave some nectar. Insects much lower in the scale than wasps 

 frequently use the perforations made by species of Bombus, as 



* I have found flowers of Vaccinittm coryinbosum perforated at Newton, Mass., but did 

 not see the insects which made the perforations, 



t The flowers are adapted to long-tongued insects, and, as Mr. Robertson informs me, 

 are rcgulcrly visited by Bombus Pennsylvanicus $ and a species oi Bonibyliiis. 



