LEPIDOPTERA OF NEW YORK AND NEIGHBORING STATES 27 



fore wing of the Jugatae; and there is occasionally a cross- vein in the 

 anal region. The discocellular is divided into four parts by the three 

 branches of media : upper, middle, and lower discocellulars (udc., 

 mdc., Idc.), and the false base of media-three (m-cu.)- In the hind 

 wing the humeral is usually replaced by a short spur from the base 

 of the subcosta, which may not reach the margin. 



The Jugatse have a special lobe on the inner margin of the fore wing, 

 the jugum (fig. 40). In the Hepialidae this slips under the hind wing 

 in flight and helps the wings to work together. 6 In the others it over- 

 lies the hind wing and is sometimes called a fibula. In most cases the 

 wings are attached to each other by a bristle or group of bristles, the 

 frenulum, which is attached to the base or the humeral angle of the hind 

 win&. The frenulum either runs through a hook, the frenulum hook, 

 attached to Sc near the base of the fore wing ; or under a tuft of scales, 

 the retinaculum, spreading up fanlike from near the base of Cu. The 

 male almost invariably has a single frenulum running through a hook; 

 the female has usually several bristles (the approximate number char- 

 acteristic of the family) held merely by a retinaculum. In several 

 groups (some Pyralididae, some Pterophoridae, ^Egeriidae, Euteliinae) 

 the freuulum of the female is also simple, but the hook is represented 

 at most by a second tuft of scales. In many forms there is no attach- 

 ment between the wings, which merely overlap; in a very few 

 (.^Egeriidae, Pterophoridae) the inner margin of the fore wing and the 

 costa of the hind wing bear series of recurved spines, which interlock 

 (fig. 223), the hamuli. 



In the males of many species the wings bear scent glands. Sometimes 

 these are merely scattered, associated with special scales, the androconia, 

 which are designed to spread the scent, (as in Pieris and Eurymus). 

 Frequently there are structures developed for their protection; as, 

 for instance, the pocket on Cu in Danaus, on the inner margin in Carsia, 

 the folded inner margin of many Olethreutes (fig. 266), of Lobophora 

 and Heterophleps, and so on. The costal edge is particularly apt to 

 be folded over, forming the costal fold (fig. 265, 306), and this may 

 contain a large tuft or mass of androconia, as in a large part of our 

 Hesperiinae and Tortricidae. In some instances the secreting area is 

 clothed with special scales, forming a stigma (fig. 249). This is usually 

 easy to see, but in such forms as Cercyonis and a few Pamphilas it 

 is easiest to moisten the wings with chloroform or benzine and hold 

 the butterfly to the light. When not specially noted, the location of 

 a stigma is the upper side of the fore wing below the cell, in the 

 Satyrinse and Hesperiidae, or at the end of the cell as in Thecla. 



*A somewhat similar lobe occurs on the hind wing of some male Geometridse and Tortricidse (fig. ? 

 but probably with the function of a scent organ. 



