496 



NATURAL HISTORY OF ARTHROPODS. 



FIG. 623. Chrysalis of 

 Terias. 



quite common in 



FIG. 624. Terias lisa. 



are regarded in Europe as being among the list of his greatest insect enemies. Some 

 of the South American species are very beautiful, and have the lower wings on the 



under side marbled with black and yellow. Such. are P. proto- 

 d'ice, and P. xanthodice; while P. cratazgi and P. hippia represent 

 a group in which the white wings are very distinctly marked with 

 black along the course of the nervures. 



The genus Eurema^ better known as Terias, is of considerable 

 extent, one hundred and fifteen species having been described. 

 They are nearly all of various shades of yellow, from pale lemon 

 to the deepest orange, with black borders of various widths and 

 patterns, and are found in all parts of the globe, excepting Europe. 

 Some of them are very beautiful, the rich orange field strongly 

 contrasting with the black margins. We have eight species in 

 our lists as natives of the United States, the most striking of 

 which are T. nicippe and T. proterpia. The former of these is 

 the southern states, and sometimes 

 travels as far north as New York, while the latter, though 

 very abundant in Mexico, has only, as far as our territory 

 is concerned, been taken in Arizona. T. lisa is remark- 

 ably common over a great portion of the northern and 

 eastern states, and may sometimes be seen in almost 

 countless numbers wherever its food plant, Cassia chamce- 

 crista happens to grow. It is citron yellow, with narrow black borders, and is one of 

 the smallest of our butterflies. The caterpillars of the genus are mostly green, with 

 various stripes of white or yellow. 



A very curious insect belonging to this group, which undergoes its transformation 

 in a community, a large flask-like nest serving as the home of the whole brood, in- 

 habits the table-lands of Mexico, and has been described by Professor Westwood under 

 the name of Eucheira socialis. The nest is parchment-like in its texture, is aboiit eight 

 or ten inches in length, and is suspended from the branch of a tree, somewhat after 

 the manner of many wasps. Instances of Lepidoptera living thus in families are 

 extremely rare among the butterflies, and the present species is consequently of con- 

 siderable interest. The imago is blackish-brown, with paler bands and streaks, and bears 

 great resemblance to some species of the Heliconidas. Allied to this is another genus, 

 containing many species, called by Hiibner Dismorphia, and, afterwards, by Dalman 

 changed to Leptatis. The former name, however, generally holds among naturalists. 

 The species are variously colored, shades of yellow, brown, and greenish being most 

 apparent among them. The great peculiarity in their history is their mimicry in form 

 and colors of the species belonging to a totally different group, viz., the before-men- 

 tioned Heliconidrc. These latter insects are, as we have seen, a sub-family of the Nym- 

 phalidse, and are distinguished by the seci-etion of an acrid and offensive fluid, which 

 protects them from the attacks of birds and other enemies. The species of the genus 

 Dismorphia which imitate them are found in company with the Heliconias, and resem- 

 ble them so much in color and form that among a number of individuals they are 

 hardly to be separated without very careful observation. Darwin says: "From the 

 fact that the Heliconidae are colored in their usual manner, while the others depart 

 from the general coloring of the groups to which they belong, it is clear that the latter 

 are the imitators and the Heliconida? the imitated. Mr. Bates, therefore, infers that 



