14 Watson, Calinaga, Single Gemis of a Sub-family. 



I. The first part of the costal nervure from its origin 



at the base of the wing up to its emission of the 

 precostal nervule I term the antecostal Hmb. 



II. The basal portion of the subcostal up to the 



emission of the short spur which in reality closes 

 in the basal cell (as the discocellulars close the 

 discal cell) I term the medio-costal. It is generally 

 weaker than the antecostal limb. 



III. The short length or spur between the costal and 

 sub-costal 1 term the interno-costal limb. It is 

 generally the weakest part of the basal cell. 



IV. The other stretch of nervure between the pre- 

 costal and the costal proper (in reality of course 

 a part of the costal) I term the disto-costal limb. 



And it is the relative length and strength of these four 

 limbs which give all the character to the size and shape 

 of the basal cell. Now while the disto- and the ante- 

 costal are generally well formed, the medio- and interno- 

 costal are weaker. In Papilio zalmoxis and Eurycus cressida 

 they are of equal value ; thus a well-formed, diamond- 

 shaped basal cell. But in Danais, Hestia and other allied 

 genera, the ante- and medio-costals are long and lie in 

 apposition, whilst the disto- and interno-costal are so very 

 short that there appears to be no basal cell at all, and only 

 on careful examination is it made out ; whilst, as perhaps 

 its antithesis, Papilio montezuma has an extremely short 

 medio-costal and the interno-costal is as long as the disto- 

 and ante-costals together. 



In those cases where there is no basal cell at all, as 

 Hypolynmas, Aporia, Pieris and others, it is because there 

 is no interno-costal. 



The extreme value of the study of the morphology of 

 the basal cell is only apparent when large numbers of 

 butterflies are systematically examined, and their relation- 



