BY FREDERICK A. A. SKUSE. 33 



Observations. 



k. Generally the longest transverse vein of the wing, and of the 

 highest systematic importance. 



p. and q. Usually present. 



p. The absence of this vein is characteristic for some families. 



q. Sometimes meeting h at a very acute angle or running into 

 the border without having met that vein ; in all cases dividing 

 the space between g and h into two parts. 



r. Occasionally giving I'ise to rudimentary branches or axillary 

 veins (vencE axillares), or less frequently to complete longitudinal 

 veins (in the case of such a development, the foremost of the 

 veins is generally connected near its base with h, by a transverse 

 vein), still i-egarded as axillary, but may be numbered as the 

 seventh and (if another) the eighth longitudinal A^eins. 



V. In some cases meets g before reaching the margin. 



Cells. 



A middle space or band extending from the base of the wing 

 to the tip, separates the three anterior sections divided by the 

 three longitudinal veins belonging to the anterior main trunk, and 

 the three posterior sections resulting from the longitudinal veins 

 of the posterior main trunk ; these three sections in each case are 

 styled exterior, middle, and anterior, and may be again divided 

 into smaller cells. 



A. First costal cell {cellula costalis pi'iina). 



B. Second costal cell (cellula costalis secunda). 



C. Third costal cell {cellula costalis tertia). 



D. Marginal cell {cellula inarginalis). 



E. Submarginal cell {cellula submargitialis). 



F. First posterior cell {cellula jwsterior prima). 



G. Second posterior cell {cellula jwsterior secunda). 

 H. Third po.storior cell [cell ala posterior tertia). 



1. Discal cell {cellula discoidalis). 



