50 PROCEEDINGS OF THE ACADEMY OF 



of plants, and never forsake them until fitted for winged existence; 

 while the Zygsenidse pass therein when about to change into 

 chrysalides. There may be instances where the entire suite of 

 changes is affected in such retreats. It is well known that many 

 of the caterpillars of the genus Gracillaria among the Tineids, and 

 the genus (Enectra among the Tortricidse, possess similar boring 

 propensities. Higher up on the scale of lepidopterous life the genus 

 Nonagria of the family Leucanidse imitate still more closely the 

 habits of the Zygaenidse and JEgeridse, in feeding in the stems of 

 reeds and grasses. There may be cited instances among the 

 fiombycinse, as the Hepdlidse. Our own Cossns robin ae, Peck, is 

 a happy illustration. The existence of a similar habit among this 

 latter famity, to that which the Leucanidse, Zygaenidas, and JEge- 

 ridae possess, does not argue in favor of the view that it constitutes 

 a link in the chain which has led from the Noetuidae to jEgeridse. 

 It shows that this family constitutes a small branch from the 

 Noetuidae. 



The presence of this habit among such low forms as the Tortri- 

 cidse and Tineidae embrace, which have deviated but slightly from 

 primitive habits, would seem to argue for analogous habits among 

 some unknown individuals of the Hydrocampidse. When these 

 forms in their larval condition are made the subjects of special inves- 

 tigation by naturalists, and new tj< pes or new individuals of existing 

 types are brought to light, it may be the good fortune of science 

 to record types which, instead of constructing cases like those 

 quoted above, derive the same essential benefits by boring into 

 the stems of submerged plants, or into the veins or parenchyma of 

 their leaves, like the members of the Tineid genus Lithocolletis 

 which mine the leaves of various plant-species from their under 

 surface and eat their cellular structures. These beings, it is true, 

 must necessarily be very diminutive in size. 



Those which have denied themselves such comfortable and pro- 

 tective dwellings as are afforded by cases and tunnels, in con- 

 sideration of the various defensive appliances with which nature 

 has endowed them, are very numerous. So familiar are these, 

 even to the most casual observer, that it does not behoove me to 

 give the barest recital of a single example. Indeed there are cases 

 where these external tegumental^ weapons, by themselves, do not 

 conserve to individual safety ; and their unfortunate possessors 

 are constrained to construct immense webs which afford com- 



