30 THE COCCIDAE 



they are probably true ocelli. In the Diaspidinae there are three 

 pairs of ocellanae, a pair of large dorsal and a pair of large ventral 

 oeellanae and a pair of minute subdorsal oeellanae. These latter 

 are designated as eyes by Newstead and the large ocellanae as 

 ocelli while in Lichtensia, where there are five pairs of ocellanae. 

 two pairs of ventral ocellanae, two pairs of dorsal ocellanae, and 

 a pair of lateral ocellanae, the latter are considered as eyes and all 

 the other ocellanae as ocelli. True ocelli are never present in 

 immature insects of this order and when present in adults are never 

 more than three in number. A very different nomenclature is used 

 by Signoret for the ocellanae. There is no reason for considering' 

 any of the pairs of ocellanae as eyes or the homologues of primary 

 eyes. The pair of small ocellanae in the Diaspidinae and one 

 pair in other male coccids may prove to be homologous with the 

 true ocelli of other insects. 



Antennae. The antennae are long and prominent in the 

 active species and usually consist of about eleven segments. This 

 number is greatly reduced in the inactive species where the 

 antennae may be wanting. In the Diaspidinae each antenna is 

 generally represented by a minute tubercle bearing from one to 

 four long setae. Where the antennae are large, the distal segment 

 is usually much larger than the others and is sometimes thickened 

 or clavate and irregularly indented or notched. The notches cause 

 this segment to appear as if subdivided or composed of several 

 subsegments. These have been described by some writers as true 

 segments. The indentations mark the location of the attachment 

 of setae. The comparative length of the various segments of the 

 antennae, particularly in the Briococcinae and Lecaniinae, have 

 been used extensively for the separation of genera and species. 

 The variation in the length of the different segments is usually 

 expressed in the form of a formula, thus: (3, 4), 7, 2, (1, 6). 

 The numbers are the numbers of the segments, the longest segment 

 is always indicated at the left end of the formula and the suc- 

 cessively shorter ones are arranged in order from left to right 

 while those of the same length are enclosed in a parenthesis. A 

 formula giving the actual length in microns is used by some 

 authors. Kellogg and Bell have shown from an examination of 

 several individuals from the same colony that there may be enough 

 variation between the segments of the two antennae of the same 

 individual to place them in different genera. This was confirmed 

 by Thro from a study of certain species of Lecaniinae. The 

 number and arrangement of the setae borne by the antennal 



