178 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



much broadened, the anterior part being twice as broad as the thorax ; 

 this broadening is due to the development of broad lateral ridges. 



PAPILIO CRESPHONTES Cramer 



Giant Swallowtail 

 Plate 31, Figure 1 ; Plate 32, Figure 1 



Occurrence. — Formerly frequent but at present not occurring in the 

 District area, although in certain places not far from the District, 

 both in Maryland and in Virginia, it is not uncommon. Irvin N. 

 Hoffman tells me that this species is to be found about Great Falls. 

 The only one I have ever seen here v^as noticed at Cabin John in 

 May, 1908. Dr. William Schaus informs me that he has seen it here. 

 Herbert S. Barber took one at Plummers Island, Md., on July 1, 1913, 

 and this specimen, now in the National Museum, represents the last 

 record for the District area. 



There are three specimens from the District in the Schonborn 

 collection taken on May 3, 4, and 9, and a pupa without date. Frank- 

 lin Sherman, jr., mentions having captured a specimen in Maryland 

 8 miles from Washington. 



Seasons. — There are presumably two broods in the District, one 

 flying from early in May until toward the end of June and the second 

 flying from about the middle of July until after the middle of 

 September. 



Habits. — The flight of the giant swallowtail, though strong, is 

 leisurel3^ The wings are flapped rather slowly, and the insect sails 

 frequently, sometimes for long distances. Though quite different, 

 the flight resembles that of the milkweed butterfly {Danaus 'plexi'p- 

 pus) more than that of any of our other swallowtails. 



When on the wing this butterfly is at once distinguishable by the 

 great contrast between its brown upper and bright yellow lower 

 surface. 



It is fond of flowers and where it occurs it is a frequent visitor to 

 gardens. It is also fond of sipping moisture from mud and is some- 

 times seen thus occupied in farmyards. 



Caterpillar. — The caterpillar, which in the South is known as the 

 " orange dog," is nearly 2i/2 inches long when fully grown. It is 

 dark brown with the hinder end yellow, a large yellow saddle-shaped 

 spot formed by the union of two large more or less triangular lateral 

 spots in the middle of the body, and a broad yellow stripe reaching 

 from the head to above the last pair of true legs. 



It feeds on a wide variety of different plants, though chiefly on 

 plants of the orange family (Rutaceae). In this region it is to be 

 looked for particularly on the prickly-ash {Zanthoayyhmi ameri- 

 canv/m) and on the hoptree {Ptelea trifoliata) . 



