150 THE COCCIDAE 



shellac is said to be artificially colored with orpiment. Lac is 

 extensively used for making the finer kinds of sealing wax, and 

 is the chief ingredient in most of the wood polishes, besides the 

 regular lacquer varnish used to coat the boxes, cabinets, and toys 

 known as lacquer ware used so much in China and India. The 

 lacquer ware from Japan, however, is polished with a varnish 

 made from the sap of one of the sumac trees (Rhus venix) and not 

 from the insect lac. ' ' The coloring matter secured from the bodies 

 of the lac insect is very similar to that obtained from the cochineal 

 insect. Species of the genus Tachardia are found in most parts 

 of the world. The following description is based upon the 

 admirable account by Green of the development of two species of 

 Tachardia, fici and albizziae. While it is quite likely that other 

 species will differ somewhat in minor details from this account, 

 yet the discrepancy is not likely to be great. 



The nymphs of the first stage have a subdepressed body, are 

 elongate oval in outline with well developed legs and antennae and 

 an anal ring with six anal ring setae. They resemble somewhat 

 in general outline a young mealy-bug, but differ from these insects 

 in that their body is naked, not covered with mealy wax, and are 

 bright red or yellow in color. The antennae consist of six seg- 

 ments, of which the third is greatly elongated and enlarged on the 

 distal half, also the distal segment or sixth, as well as the fifth, 

 bears two very long slender setae. The rostrum is large and 

 conspicuous. The legs are distinct and normal in form. The anal 

 ring is large and each of the six anal ring setae is attached to a 

 small circular plate. The thoracic spiracles are small and incon- 

 spicuous. There is apparently a distinct canella with spiracerores 

 associated with each mesothoracic spiracle, but no such structures 

 are connected with the metathoracic spiracles. 



The young nymphs soon begin to excrete wax. If one that is 

 two or three days old, is examined, it will be found that the entire 

 body is completely encased in a thin homogenous sheet of wax. 

 Green states that this wax first appears in the form of plates which 

 with increase in size coalesce. The form and general distribution 

 of the wax and the absence of cerores on the surface of the body 

 has led to the suggestion that the wax is the product of all the 

 hypodermal cells excreting together and not of certain cells con- 

 nected with cerores as in most coccids. A histological study of 

 these cells has not been made so far as I am aware. 



