446 



AN INTRODUCTION TO ENTOMOLOGY 



and, therefore, it is necessary to learn the terms used by an author in 

 order to understand his descriptions. The most detailed and sys- 

 tematic terminology that has been proposed is that of MacGillivray 

 ('21). Some of the many terms adopted by this author are defined 

 below. 



The cerattibcB. — In the Diaspidina? and in some species of several 

 other subfamilies, the terminal portion of the outlet of some of the 

 wax-glands is an invaginated cuticular tube. The inner end of this 

 tube is truncate, and, in the Diaspidinaj, bears a perforated knob. 

 This invaginated cuticular tube is termed a ceratuba. The ceratuba) 

 vary greatly in length and in shape ; in some the greater part of the 



tube is reduced to a fine thread, 

 with a bulb-like inner end. A 

 few ceratubas are represented in a 

 diagram given later (Fig. 522). 

 The openings of most ceratubas 

 are flush with the body-wall, but 

 some of them open through plates 

 in the marginal fringe. The dif- 

 Several types of openings of ferent types of ceratubas have re- 

 ceived distinguishing names 

 formed by combining a prefix with the word ceratubae. 



The cerores. — The various types of outlets of the wax-glands in 

 which the cuticula is not invaginated so as to form a ceratuba are 

 termed cerores. The openings of cerores through the cuticula vary 



Fig. 520.- 

 cerores 



Fig. 521. — Diagram of a pygidium of a diaspid: a, anus showing through the 

 body; d, densariae; g, genacerores; i, incisions; /, first pair of lobes; pe, 

 pectinae; />/, plate; .s, setae; f, vagina. 



greatly in form; several types of these openings are represented in 

 Figure 520. While in most cases the openings of cerores are flush 

 with the general surface of the cuticula, in some coccids (Ortheziinae) 

 the cerores open through spines. There are also variations in the 

 grouping of the cerores. Each of the various types has received a 

 technical name formed by combining a prefix with the word cerores. 



