[7] COLLECTING AND PRESERVING SCALE INSECTS — COCKERELL. 



possible, always get plenty of material. Well-known species can usn- 

 ally be recognized from very little material — even single scales ; but 

 new species, or species in difficult groups, require, as a rule, a fair num- 

 ber of specimens, in order to be properly studied. This is in order that 

 some may be prepared for the microscope and others left in the natural 

 state, and also that the normal amount of variation may be ascertained, 

 and, if possible, both sexes described. Yery often I receive one or two 

 scales only of species of Eulecanium — an extremely difficult group. It 

 may as well be understood that such material, in the present state 

 of our knowledge, is practically worthless. 



In the case of new species, it is very desirable to have enough to 

 distribute cotypes to the various workers in Ooccidfe. and some of the 

 museums. 



Care should be taken to obtain both sexes whenever possible. Often 

 the male scales will be conspicuous and the females very inconspicu- 

 ous, as in some Diaspime, or, vice versa, as in many Lecaniinse. The 

 male scales may occur on the leaves, while the females are on the twigs; 

 hence various parts of the plant should be examined. 



PRESERVING COCCID^. 



I. Treatment in the field. — As a general rule, OoccidaB should be 

 preserved dry in situ on the plants. With the softer species, alcoholic 

 material is often useful, but it can not be too strongly insisted that this 

 should only supplement dry specimens. The mealy bugs, for example, 

 can hardly be determined from alcoholic material alone, because the 

 characters of the cottony secretion are lost, whereas they can fre- 

 quently be described quite accurately from dried examples.* I have 

 had collections of alcoholic CoccidiB sent to me at considerable trouble 

 and expense, which would have been much more valuable if simply sent 

 in paper envelopes at a minimum of cost and inconvenience. 



It is an excellent plan for the collector to have a number of fairly 

 large envelopes, or better, flat card boxes, and place each gathering 

 in one of them, writing on the outside the locality, date, name of plant, 

 name of collector, and any remarks that seem desirable. The envel- 

 opes have the advantage of occupying a very small space, and are very 

 convenient for mailing; their disadvantages are two, first they may 

 crush some scales, particularly Lecanium and Ceroplastes; and second, 

 they may not retain any parasites which happen to issue from the 

 coccids. Card boxes about 6 inches long, 3 wide, and 1 high, would 

 probably serve as well as anything that could be devised, provided 

 that the collector could aflbrd to take with him such bulky objects; 

 failing these, however, it is to be understood that in nine cases out of 

 ten the material placed in envelopes is perfectly satisfactory. 



Kothing air-tight, as tin boxes or glass tubes, should be used for 

 fresh material, as it will almost invariably mold. 



* It may be added, that alcoholic material is often hard to clear for the microscope. 



