1888.] 59 



I first obtained the white form, along with the mature scales, on 

 Adiantwm capillus veneris in the conservatory of Mr. W. Morris at 

 Deptford, in April, 1887 ; and in February last I received some, on 

 another fern, from Rev. W. F. Johnson, Armagh. I have also had the 

 mature form from Mr. P. Cameron, Sale, on Bryophyllum calycrinwm 

 and Asparagus plumosus. 



Lecanium bitubeeculatum. 



Lecanium hituherculatum (Targ.-Tozz.), Sign., Ess. Cochen., p. 244. 



$ scale chocolate-brown or grey-brown, with yellowish tints in places, broad- 

 oval, very convex, the upper part of irregular contour, with two pairs of dark, shining 

 tubercles, each tubercle of a pair placed near to and in a line with the other, the 

 posterior ones larger, more conical, darker, and more polished than the anterior ; 

 between the tubercles, on the median line, is a broad, flat ridge, which is continued 

 forwards for some distance, and then ends abruptly at a large depression, from which, 

 at a low level, a very fine raised line goes to the anterior margin : behind the tubercles 

 the median flat ridge extends a little, and then merges into a slight carina, which 

 goes to the anal cleft ; this is long, fusiform, open, and the aperture has raised 

 margins ; the scale has a broad marginal field more or less freckled or banded with 

 yellow or ashy-white, and with large confluent punctures ; on the posterior portion 

 of the sides of the scale this field is crossed by four or five short carinas, and one, 

 immediately below the larger tubercle, longer and stronger. 



Length, 4"5, breadth, 3, height, 2 mm. 



The specimens I have being des'sicated I have to borrow from Signoret the de- 

 scription of the parts I am unable to see : — " The antenna? have 7 joints ; the 4th 

 being the longest, with four long hairs at the extremity ; 5th and 6th the shortest, 

 7th a little longer, equal to the 3rd. Legs difficult to eliminate, twenty examples 

 were destroyed before a view of an entire one could be obtained ; tarsus one-third 

 less than the tibia, with three hairs towards the end ; claw rather broad at the base, 

 with two digitules en forme de cornet. 



" The ? larva has 6 joints in the antennas, of which the 3rd is the longest. 

 The (J larva is much longer, and has 7 joints in the antennas, of which the 7th (very 

 long and equalling the 4th) has four hairs at the end. The dorsal surface has very 

 small and proximate cellular punctures, especially towards the margin." 



The $ imago is not described. Of the $ , Signoret says the scale is is very 

 variable in size, sometimes attaining 5 mm. in length, 4 in breadth, and 3 in height, 

 according to the circumstances of its position on a small or large site. His figure 

 represents the dorsal tubercles as of nearly equal length, whereas his description 

 states that two are smaller than the others ; a lateral tubercle is also shown which 

 is not mentioned in the description, and which I do not find ; it is doubtless meant 

 to represent the carina below the larger tubercle. The lateral carinas are not figured 

 nor described, the smaller ones are frequently not very evident, but the large one 

 always is. But in all the main points my examples agree so well with Signorct's 

 description as to leave no doubt of the specific identity of this remarkable form. 

 It appears to be subject to some variation, for Signoret mentions that, on some of 

 the specimens he received from Florence the anterior smaller tubercles were wanting ; 



