12 INSECTS NOXIOUS TO AGBICULTUBE. 



4. The fall-grown insect. Here there is almost unlimited 

 variety of form, colour, and habits. The insects may be naked 

 or covered, active or stationary. In the Diaspidince the process 

 just described is repeated : the female slips out of her second 

 skin, but still keeps both it and the first over her, adding more 

 fibrous secretion from the spinnerets ; so that, in fact, she lies an 

 inert, legless, slug-like object, under a covering composed partly 

 of the two skins, partly of secretion. (See Plate i., Fig. 3 : a is 

 the discarded larval skin, b the discarded skin of the second 

 stage, both being used as part of the shield. In the genus 

 Aspidiotus these skins would be in the centre instead of at one 

 end.) In the Lecanidina (except in one single genus) and the 

 Coccidince the second skin is discarded altogether ; but the insect 

 may either construct a new shield or remain naked, may be 

 either with or without legs, either active or stationary. Once 

 this last stage of her existence entered upon, the female prepares 

 for laying her eggs. In most species the services of a male are 

 needed ; in some, as far as can be made out after investigation 

 of many years, no males are found. The female, if naked, 

 either hatches her eggs in her own body or lays them on the 

 plant; if covered, she fills her shield with the eggs. The naked 

 insects often cover the eggs themselves e.g., Lecanium hemi- 

 sph&ricum ; or, again, deposit them in an ovisac, a mass of 

 cottony secretion e.g., Pulvinaria camellicola or leery a purchasi. 



II. THE MALE INSECT. 



It has been remarked above that, as the full-grown, males of 

 the Coccididae are destitute of any organs for feeding whatso- 

 ever, there is 110 reason for making systematic attacks on them 

 for economical purposes. Their function is simply to impregnate 

 the females, and their life at this stage must necessarily be very 

 brief. It will suffice in this place to observe that in all cases 

 these males are small, two-winged flies, their size varying from 

 about g^in. to Jin. in length ; colour usually yellow or red ; 

 wings longer than the body, hyaline (glassy) and often 

 iridescent, and, in repose, lying flat, partly crossing each other 

 The antennse are long, slender, and hairy, consisting of nine or 

 ten joints. The legs are also slender and hairy, the tarsus 

 having only one joint, and terminating in a single claw. The 

 insects are generally very active. Types of antenna, foot, wing 

 and haltere, and a diagram of the arrangement of the eyes and 

 ocelli, are given in Plate i., Figs. 7, 12, 13, 14, 15, 17. 



