PLTJME-MOTHS OF CEYLON. 



Identification. 



One of the great difficulties of all local workers at zoology in the 

 tropics lies in the identification of their specimens. "Si nomina 

 nescis, perit et cognitip rerum," and nowhere is this truer than in 

 entomology. Considerations of space have prevented my giving a 

 detailed description of all the species, but the tables will facilitate 

 determination, which may then be confirmed by reference to the 

 descriptions and figures cited under each species. 



There should be little difficulty in identification by means of the 

 analytical keys to the genera and species, but a few words of expla- 

 nation may be advisable. Each key is dichotomous throughout, 

 that is to say, each heading is subdivided into two until the final 

 results are reached. Each head is numbered consecutively, and 

 each subdivision of a head is made to refer either to a final result or 

 to a following head. There are two stages in the identification of 

 any species, the finding first of its genus and secondly of its specific 

 name. 



To take an actual example. Firstly, we have to note whether 

 the wings are fissured or not ; we find they are fissured, and are 

 referred to the number 3 on the right of the page. Now, turning to 

 the number 3 lower down on the left of the page, we see that the 

 fore wings have two lobes and arc referred to the number 4, which 

 wo follow down in the same way. The cilia contain distinct scale- 

 tufts, which brings us to number 5. The dorsal cilia of third 

 segment of the hind wing contain a distinct scale-tuft, which refers 

 us to number 9. The second segment of the fore wing is distinctly 

 broad, so that the specimen must fall under number 10 and, as 

 the segments of the hind wing are differently shaped, it must be a 

 Platyptilia. 



The second stage is to find the specific name. We turn to the 

 Synopsis of the Species of Platyptilia and note that our specimen 

 has the abdomen shorter than the dorsum of the fore wing, its 

 pectus is not yellow, and the large scale-tooth on dorsum of third 

 segment of the hind wing touches the apex, so that the moth must be 

 P. pusillidactyla, an identification whose accuracy is strengthened 

 on turning to that species by the fact that we bred it from a boxful 

 of flower and seed heads picked off a Lantana bush. 



In drawing up the key to the genera some difficulties have pre- 

 sented themselves, due to the fact that I have endeavoured to make 

 use only of characters easily made out by means of a simple lens at 

 most, without the aid of the microscopic manipulation necessary 

 to determine details of neuration, &c. ; however, it is hoped that 

 local collectors will find the table quite workable. Should examin- 

 ation of the neuration be necessary the following method may be 

 adopted : take a glass slide and smear on its centre a thin layer of 

 clove oil with a fine brush, remove the wings and place them in 



