30 NATURAL ENEMIES OF THE COCCIM3. 



as a rule contains a single parasitic larva, or if more 

 are present there is but one large swelling, which 



gives the scale (?) a .... gibbous form I 



should add that the portions of the dermis affected by 

 the parasites are devoid of the ordinary reticulation, 

 and in the specimens which are much swollen the 

 integument becomes almost transparent. It is some- 

 what exceptional for the perfected parasites to escape 

 through the dermis by making and leaving the usual 

 perforations ; they more frequently leave the body of 

 their host through the anal cleft, as there is no other 

 means of escape if they have not made such for them- 

 selves. When this is the case they seem to have com- 

 pleted their metamorphoses below the ventral skin of 

 the host, thus the scale remains apparently intact, and 

 one can easily see how such specimens would appear 

 perfect; they, however, have had the whole inter un- 

 eaten away, but when the parasites escape through the 

 dermis the ventral surface generally remains entire. 

 .... The foregoing is sufficient to show that the 

 greatest care should be exercised to select specimens 

 free from parasites for description ; for while some of. 

 these may not materially affect the exterior of the 

 scale (?) they are quite capable of malforming the 

 antennas and legs, especially such species as feed upon 

 the larvae and ova when in the scale." It is a remark- 

 able fact, but, as in many similar cases, the parasitic 

 larvae rarely cause the death of the host until the very 

 last stage is reached. It is no uncommon thing to find 

 a parasitised female laying apparently her full comple- 

 ment of eggs, but the latter sometimes fall a prey to 

 the parasitic larvae. 



In the Lecania the earliest external sign of parasitic 

 disease is usually indicated by the yellowish colour of 

 the insect, and later by the swollen appearance of the 

 integument, which form it usually retains, but in 

 many cases assumes the single or double mammiform 

 character. 



The following is a list of the Hymenopterous para- 



