INSTRUCTIONS FOR COLLECTING INSECTS. 189 



the relation of the segments to each other ; all protuheranccs should 

 be designated, and the nature of the dermal appendages, if any, 

 noticed ; the number of feet, abdominal and anal prolegs, and the 

 position of the latter with reference to the plane of the body, on what 

 rings they are absent or are weakly developed, or are modified. 

 To indicate the number and situation of the legs and prolegs, I use 

 the following formula, which is not intended to supplant description: 

 Every larvae having thirteen segments, including the head, the dots 

 indicate segments without feet thus : ( • f • • i • • i)- The formula rep- 

 resents the most common form, that having sixteen legs. 



4°. Its peculiarities of coloring ; giving first the general color of 

 both head and body, and then the ornamentation on each. 



5°. Tlie date at ichich it began to prepare for pupation, and the nature 

 of its preparations. 



6°. A descrijition of the p)upa itself. It is not advisable, usually, to 

 make a description of this from the first or a single specimen. 



7°. The date at lohich it became a perfect insect, and method of its 

 escap)efrom the cocoon, if it has one. 



8°. The number of broods of the perfect insect during one season, and 

 whether the period of larval developmen\fc is annual or bi-annual. 



The observer should also endeavor to ascertain and describe — 



9°. The egg of the 'perfect insect, its form, color, and peculiar mark- 

 ings under a lens. When the perfect insect of a larvae is once 

 known, this and the following can be ascertained by preserving the 

 egg layer. 



10°. The appearance of the young larva on first emerging from the 

 egg ; the successive changes in appearance it undergoes during its 

 moultings until it reaches the condition indicative of maturity. 



11°. The habits of the larva, including everything pertaining to 

 larval life, from the time of leaving the egg to maturity, whether 

 characteristic or not. 



12°. The habits of the perfect insect, as far as they can be ascertained. 



The student should begin, in the first instance, with the endeavor 

 to refer his caterpillar to one of the larval forms characterized here- 

 tofore, in order to gather his descriptions under general heads. Prob- 

 ably he will not be successful in referring it to any there indicated, 

 for several groups have been omitted in consequence of the difficulty 

 of representing them by any graphic characters. These he may 

 arrange under any general heading that appears most appropriate to 

 himself. Each vessel containing a larva should be marked with a 

 special numeral, beginning with one for the first, and so on, and the 

 description should be indicated by the same number ; if the pupa is 

 removed from the vivarium in order to receive another larva, (for two 

 dissimihir larvae should never be placed in the same vessel at one 

 time^) that containing the pupa should be designated by the number 

 referring to the description of tlie larva, and the numeral should be 

 marked on a little square of paper and fixed on the pin containing 

 the perfect insect when it appears and has been killed and pinned. 

 A specimen of the mature larva described, whenever it can be ob- 

 tained, should be drowned in alcohol and enclosed in a piece of foil, 

 such as is now commonly used for wrapping fine-cut tobacco, with 



