122 



FORM OF THE PECTKN IN CERTAIN BEES. [Mar. 25, 



Is it possible that these tubes, which, as I have observed, are re- 

 markably similar in appearance to those in the spider's spinneret. 



may be of the nature of salivary glands ? It is easy to imagine the 

 use of such a provision in the management of the materials of the 

 nests and the storing of food, even if not also in the assistance of 

 digestion ; while it appears to me that there is analogy in favour of 

 such a supposition, the House-fly exuding from its mouth a drop of 

 moisture while feeding on sugar or other hard substance, while the 

 Gnat, with still another form of mouth, is supposed to inject a 

 poison into the wound inflicted by its proboscis. 



I beheve that somewhat similar tubes exist in the mandibles of 

 some of the Bees and Wasps. 



The mandibles of some of the ApidcB have a transverse ridge of 

 strong hooked hairs (besides other hairs in various parts). In the 

 mandible of Apis mellifica ^ , they are very visible. 



With the above objects I send specimens of the hind wings of 

 various Hymenopterous Insects, the observation of which has con- 

 firmed me in my former opinion as to their usefulness as distinctions ; 

 but as I have arrived at no new results, not having had the means 

 as yet of representing more than a very limited number of genera, I 

 will only remark on one variation from the usual arrangement of the 

 distal hooks, which occurs in the genera Sphecodes and Halictus. 



The distal hooks of the Bees are usually at regular or at regularly 

 diminishing intervals ; but in these two genera, one or two of those 



various parts of insects, with the exception of those which he figures Tab, 18. R. a, 

 and which I have mentioned above as tubes " in a cluster close above the maxil- 

 lary palpus." 



