18 THE BUTTERFLIES OF NEW ENGLAND. 



A band or ribbon, made up of simple, longitudinal, parallel, muscular 

 fibres, collected into two contiguous strips, the inner the narrower, runs 

 from one end of the body to the other, near the skin, Ijctween the spiracles 

 and the ^•entral side of the body. In Euphoeades, however, the double 

 strips form on each side one broad ribbon made up of from fifteen to 

 twenty-five independent, similar, contiguous cords. Each strip is properly 

 made up of a series of bands, one to each segment, extending across its entire 

 length, and they are permeated by minute tracheal vessels running mainly 

 at rio-ht ano-les to the direction of the fibres. From the anterior end of the 

 inner strip of each segment, a slender nuiscular strap runs obliquely to the 

 middle of the ventral line of the segment. Beneath the insertion of the 

 longitudinal bands sets of nearly parallel but slightly converging l)ands 

 run to the ventral line at the middle of the front of the succeeding, or at 

 the posterior edge of the same, segment. Above the spiracles, on each side, 

 are three slightly oblique muscular ribbons, the lowermost lying nearer the 

 integument than the others, its lower edge touching the base of the 

 tracheae. These three strips are not continuous on succeeding segments, 

 but the innermost broadens posteriorly and becomes two in the succeeding 

 segment, its inner half repeating the same on the next segment and so on. 

 Beneath all these longitudinal bands, as seen from Avithin, ^. e., lying 

 nearer the integument, and at the anterior edge of each segment, a narrow 

 transverse belt encircles the whole l)ody, passing at the stigmatal line OAcr 

 the longitudinal tracheal vessel which unites two contiguous spiracles, and 

 stra})ping it to the integument. 



The flexor muscles of the true legs originate in the body just beneath 

 tlie origin of the outer of the two longitudinal muscular ribbons of the 

 ventral surface of the body, and extend to the opposite wall of the segment. 

 The muscles of the prolegs consist of flat bands forming a muscular coating 

 to the walls of the legs, passing in a direct line downward, narrowing as 

 they go ; they do not cross each other, nor pass to opposite sides of the 

 legs, but are entirely simple. 



Passing now to the muscles attached to the internal organs, we find the 

 coating of the stomach, which is a mere film, overlaid by delicate parallel 

 strips of muscular fibres crossing diagonally in opposite directions ; besides 

 these there are longitudinal muscles arranged in sets, each set separated 

 from its neighbors and composed of several slender bands, traversing the 

 entire length of the stomach ; those next the dorsal and ventral lines are 

 more prominent than the others and on the anterior are larger than on the 

 posterior half; sometimes, however, the transverse encircling muscles are 

 more highly developed than the longitudinal ; the sets on the dorsal lines 

 are united into a double band at the anterior extremity and pass to the 

 oesophagus, where they are more widely separated ; the oesophagus is })ro- 

 vided also with other longitudinal muscles, and to a less extent with trans- 



