BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [124] 



ward. The time of laying and hatching of eggs, the number from a 

 single female, the character of the eggs, general habits, records of par- 

 asites and their mode of attack — all should be entered as observed. A 

 great many species have the most curious life histories, which can not 

 be ascertained except by continued and iDersevering observation, not 

 only in the vivarium or insectary but in the field. It is almost impos- 

 sible to follow, under artificial conditions, the full life cycle of many 

 species like the Aphididte, or the Gall-flies, etc., which involve alterna- 

 tion of generations, dimorphism, heteromorphism, migration from one 

 plant to another, and various other curious departures from the normal 

 mode of develoiDment, without careful field study and experiment. 

 These studies are possible only to those who are able to frequent the 

 same localities throughout the whole year, and can hardly be carried 

 on by the traveling naturalist or collector. 



IXSTEUCTIOKS FOE COLLECTIi^G AND PEESEEVING 

 AEACHKIDS AND MYEIAPODS. 



The foregoing iDortions of this manual have dealt. almost exclusively 

 with the subject of the securing and preservation of Hexapods, but it 

 is deemed advisable to include brief instructions for the collection and 

 care of the near allies of the true insect. Spiders and Myriapods, the 

 study of which will in most cases be associated with that of Hexapods. 



DIRECTIONS FOR COLLECTING SPIDERS. 



Apparatus. — Many of the directions and methods given in the fore- 

 going pages for the collection of Hexapods apply also to the animals 

 named above. Little apparatus is necessary in the collection of spi- 

 ders and other Arachnids. The essentials are vials containing alcohol^ 

 an insect net, a sieve, and forceps. Narrow vials without necks are 

 best for collecting ]3urposes, as the corks can be more quickly inserted. 

 They should be of different sizes, from 1 dram to 4 or 6 drams, and the 

 alcohol used should be at least 50 per cent strong and in some cases it 

 is advisable to use it at a strength of 70 or 80 per cent. The net may 

 be of the same construction as that used to collect insects and is used 

 in the same way. Some arachnologists, however, use a net of a some- 

 what different make, which is much stronger. The iron ring is heavier 

 and larger than in the case of the insect net, resembling in this respect 

 the ring of the DeyroUe net. The bag is short and the handle is fast- 

 ened to both sides of the ring. This net is used for beating the leaves 

 of trees, bushes, and grass. Dr. Marx uses a net which is already- 

 described and figured under the name of the Umbrella Net (see p. 34^ 

 Fig. 52). The sieve is the same as that described on p. 35, Fig. 54^ 

 and is used to sift the spiders from leaves and rubbish, especially 



