ENTOMOLOGY IN OUTLINE— DIPTER A. 83 



or skin, and that on the fleshy part of the leaves, between these two 

 layers, these insects feed and live and pass through all their changes, 

 it will be understood how minute they, or some of them, are. It is in 

 this family, too, that we find that greatest 

 of all pests to the careful housewife, the 

 clothes-moth {Tineola hisselliclla) . This 

 is not the only culprit, however, for while 

 to the disgusted housewife, Avho finds her 

 woolens eaten full of holes, there is but 

 one clothes-moth, the entomologist recog- 

 nizes several species, all guilty of hke ^'•^•''- '''^''yetcZrem' ^'^'''"''''"'^ 

 destruction. Among these are the case- 

 bearing clothes-moth {T. pellioneUa), the tube-building clothes-moth 

 (T. tapetzella), and the naked clothes-moth (7^. hissellieUa), mentioned 

 above. 



The family Hepialidse is a small one, composed of large or moderate 

 sized moths. Its members are not sufficiently numerous to be of 

 importance economically. 



The Micpoptepygidse. The last family of this branch of the order 

 Lepidoptera is one of little importance to our readers. This family is 

 remarkable only for the reason that it reveals certain anatomical 

 features which are thought to point out an early connection between 

 this and other orders. 



Order DIPTERA. 

 (Two-winged Flies.) 



Like that of the other orders of insects, the name of this order is com- 

 posed of two Greek Avords, dis, two, and pteron, wing. As before stated, 

 the wing peculiarities have been taken by entomologists to divide the 

 orders of insects, and in this order most of the members have but two 

 wings, while in all others, as a rule, there are four wings present. But 

 even to this rule there are exceptions, as we have shown, for in most of 

 the orders some of the members are wingless, while in some, as in the 

 male of scale insects, there are two-winged insects. But the rule works 

 in the Diptera to this extent, that most of its members have two wings 

 and no more. There is in them what appears to be the rudiments of 

 another pair, in a pair of little knobbed hooks, known as halteres, 

 which occupy the place of hinder wings in the members of other orders. 

 These halteres are present even in those few species in which the fore 

 wings are entirely absent. 



As Avith the word "bug," so Avith the Avord "fiy "; it is Avrongly used. 

 To the average person, either of these terms may mean almost any kind 

 of an insect, the latter, of course, being applied to insects Avith wings 



