FAMILY EPHEMERID^. 187 



of its globular envelope, and comes forth, casting off its pupa skin, which is left partly 

 adhering to the orifice as represented in fig. 4. 



The myrmelion is a four-winged insect, at first view resembling a libellula ; but it will 

 be perceived that its antennae are peculiar, and quite diflferent from those of that family : 

 they are larger at the extremity than at the base, generally curved, and sometimes appear 

 like a hook. The eyes are wide apart, and do not touch upon the upper and posterior parts. 

 The wings are extremely delicate, like the finest gauze ; and the abdomen is rather slen- 

 der, and tapers each way. The color of the insect is brown. The wings are transparent, and 

 all the nervures are spotted with brown and white. The rings of the abdomen are brownish, 

 but much the darkest on their posterior half : the abdomen is also clothed with short 

 hairs. The wings are attached to the thorax at a distance apart, and the thorax is divided 

 into two parts, the first supporting the forewingg, the last the hindwings : the first has 

 rounded eminences, separated by oblique fissures ; the last has properly only two, which 

 are separated by oblique ridges, that begin at the sides and nearly meet in the middle. 

 The abdomen has five rings. The feet are black. Length of the larva, about ^ an inch : 

 length of the perfect insect, 1^ inch ; expanse of wing, 2^ inches. 



The species above described and figured were furnished me by Mr. J. Gebhard, Curator 

 of the State Museimi, and were procured under the limestone ledges at Schoharie. I have 

 also found the larva of the ant-lion beneath the limestone ledges near Burlington ( Ver- 

 mont) : almost every suitable place furnished specimens of the insect. 



I am unable to determine whether this American species has been described or not. 



Ephemeridae. 



Mayfly is the common name for the insects of this family. If not characterized by the 

 shortness of their lives, it is a well-known feature in their economy : they live but three 

 or four hoiurs in their perfect state ; hence the modifications of their mouth are quite dif- 

 ferent from those of the libellulidse, which have a much more prolonged existence, and 

 are therefore provided with ample means for taking sustenance. Their antennae are minute 

 and three-jointed, and their four wings are of an unequal size. The mouth is nearly obso- 

 lete or wanting, and the extremity of the body is furnished with articulated setae. Their 

 bodies are rather long, slender, and soft ; the eyes rather large, and there are also three 

 ocelli placed in a triangle between the eyes. In some species the clypeus shuts over the 

 mouth. 



The name of this family is derived from the greek ephemeras, diurnal, in allusion to the 

 shortness of their lives. The only function they perform is to couple and deposit their eggs 

 in the water. Their larvse live in the water, and their existence in this state is prolonged 

 for two or three years. They take refuge under stones, or in the earth or mud. They feed 

 upon the slimy mud that contains decomposing particles of organic matter, and which 

 suffices for their nourishment. 



