SUBFAMILY DIASPIDINAE 231 



third incisiira, the fourth group those of the fourth iueisura, the 

 fifth group those of the fifth incisura, and the sixth group those 

 located on each lateris. Since the number of lobes and incisurae 

 is usually three or less, this formula would also indicate the 

 number of incisurae, for if there was only a single incisura pres- 

 ent, the formula would consist of only two groups, if of two in- 

 cisurae of three groups. Such a formula, 0-0, 1-3, 2-5, would 

 show the presence of two incisurae, the absence of plates or pec- 

 tinae in the median incisura, the presence of one to three in the 

 second, and the presence of two to five on the lateris. The formula 

 also suggests the number of lobes present. 



In many of his descriptions Lindinger has abbreviated by 

 indicating many facts as to the pygidial fringe by the use of a 

 formula. This is well illustrated by the use of the one he gives 

 in "Die Schildlause" for Chionaspis euonymi, as follows: 

 OF,; h,; 2?,,- Dr-m; 2L2; 2P3; Dr-m; 2L3 ; 2P4; 2Dr-m; 2-3P5. 

 Translated, this formula means, no plates in median incisura, 

 median pair of lobes present, two plates and oraceratuba on a 

 latadentis in each second incisura, second pair of lobes present 

 and incised, two plates and an oraceratuba on a latadentis in each 

 third incisura, third pair of lobes present and incised, two plates 

 and two oraceratubae on latadentes in each fourth incisura, and 

 two to three plates on each lateris. 



The arrangement of the plates on the lateres in the Lepido- 

 saphini, Parlatoriini, and Diaspidini is such in many species as 

 to suggest a segmental arrangement. The cephalic group, par- 

 ticularly in the Diaspidini, generally contains the largest num- 

 ber. Where these plates are separated so that each must be con- 

 sidered separately or where the plates of the other groups are sepa- 

 rated, those of a group are enclosed in a parenthesis. The 

 groups of plates on each lateris are separated by hyphens. The 

 following shows such a formula: (1-1) -2-2- (1-1-1-1). 



The proximal portion of each of the lobes or the surface of 

 the marginal portion of the pygidium adjacent to the lobes and 

 the lateres adjacent to the latadentes usually bear small setae, 

 the pygidial setae. These setae are generally constant in num- 

 ber and position for a given species and are usually designated 

 as spines. Some of the setae are located on the dorsal aspect 

 and others on the ventral and for this reason they are some times 

 designated as the dorsal or ventral setae. There are a few 

 species in which a second row of setae, the submarginal setae, 



