BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [6] 



faunae, tliougli in the same general region. The same species of plants 

 in these localities are not infested by the same coccicls at all. In the 

 Tropics almost everything may be examined, but especially cultivated 

 plants at sea level. Palms, particularly the cocoanut, are excellent. 

 Orotons, orange trees, cotton, guava, mango, olive, Hihiscus, Acalyplia^ 

 akee, capsicum, Lantana, sugar cane, ferns, orchids, cacti, etc., have 

 proved worth examination. Even the underground tubers of yams 

 and sweet potatoes have their peculiar species. 



In Australia wonderful coccid faunae inhabit the species of Uuca 

 lyptus and Casuarina, including many gall -making forms. It is, how- 

 ever, of little use to examine these trees in parts of the Tropics where 

 they are not native but have been raised from seed. It is useful to 

 look under the bark of such trees as have loose bark, like the lignum 

 vitae of the West Indies. 



A great deal of excellent work may be done by those who receive 

 plants from the Tropics. It is, of course, extremely desirable to prevent 

 the introduction of fresh coccids into our hothouses and gardens; but 

 if, in addition to destroying the species found on plants received, the 

 owners would save some specimens for the coccidologist, it would be an 

 excellent thing. Much has already been accomplished in this way, 

 but there is a great deal of useful work still to be done; in fact, con- 

 sidering the opportunities that importers have, the results are nothing 

 to be proud of. Nor is it any satisfaction to contemplate the careless 

 manner in which infested plants are taken from hothouse to hothouse, 

 bought and sold, without any serious attempt to clean them of scale 

 insects. It is not merely a question for the hothouses, either, since it 

 is through hothouse plants that several coccids have already been 

 transferred from the Tropics of one hemisphere to those of the other. 

 Witness Orthezia insignis, for example. 



III. How to recognize Goocidce. — Ooccidae are degraded homopterous 

 insects with apterous and usually stationary females and two winged 

 (rarely apterous or subapterous) males. This definition, however, will 

 not much assist the casual observer. Attention should be directed to 

 any stationary insect with a soft body and more or less mealy powder 

 or cottony secretion ; also to any hard, naked species resembling some- 

 what half of a split pea, or to any oblong or rounded, flat, or convex 

 object, hard or soft, from the size of a pin's head to that of a waistcoat 

 button. Likewise to any whitish or grayish scurfy substance, and to 

 any small masses of wax. All such are nearly sure to be Ooccidae. 



Unskilled observers always manage to gather in, along with the coc- 

 cids, some miscellaneous material such as Aleyrodidae, Psyllidae, and 

 even fungi. But there is no harm in this. On the contrary, new species 

 of both Aleyrodidae and fungi have been found among coccid material 

 sent to me, proving quite as interesting as the coccids themselves. 



TV. How to collect. — Simply gather portions of the plants with the 

 insects in situ. If the specimens are on the bark of large trees, por- 

 tions of the bark or epidermis may be removed with a knife. When 



