36 ENTOMOLOGICAL NEWS. [February, 



of the room, and will further, unless watched carefully, eat into 

 the membrane of the more delicate wings. My practice, when I 

 want rapid results, is to get the wings into the lime solution, set 

 the dish on the window-sill outside^ drop in my acid, and close 

 the window until chemical action ceases. The wings are then 

 ready for study. It is by no means necessary to go through this 

 process with every new form. When the general course of the 

 veins is known a few scales removed on the underside, at the 

 right spot, determines the matter. Where a wing is mounted in 

 balsam after bleaching, great care must be exercised lest weak 

 veins be rendered so transparent that they are overlooked, and 

 folds must not be mistaken for veins. A fold is often much more 

 distinct than a vein, but looks solid, with irregular edges, while 

 a true vein has clean cut edges and is a tube. For forty years 

 even the best European students had mistaken a fold for a vein 

 in some ZygcBtiidce until I pointed out the error, and on the other 

 hand I was caught napping and failed to see a true vein in Cera- 

 thosia because made too transparent in balsam. 



If I have been somewhat diffuse on the subject of preparing 

 wings for study, it is only because in venation we have the key 

 to the present classification, and without it determination of 

 family is guess work, more or less correct according to the expe- 

 rience of the guesser. 



In a normal heterogeneous wing the primaries have 12, rarely 

 13, the secondaries 8 veins. On the secondaries the number may 

 be increased to twelve or reduced to four, and it is in the secon- 

 daries that we find some of our most useful characters. 



In the next paper the usual type of venation will be figured 

 and described. 



Some of the Insects collected at Jamesburg, N. J., July 4, 1891. 



HYMENOPTERA. 



By W. J. Fox. 



(The rarer species.) 



Elis 4-notata Trypoxylon tridentatum 



Pompilus fuscipennis Odynerus birenimaculatus 



Pompilus virginicus 



