SCIENTIFIC NOTES. 271 



tubercles, to distinguish them from each other, so very much 

 ahke are they. I should not like to pronounce on the identity 

 of any of them presented to me at random, though I can 

 detect certain slight differences when I have them side by side 

 for comparison. 



They all agree in having several hairs on the anterior trape- 

 zoidal tubercles and only one on each of the others. On the 

 trapezoidals (anterior) they all tend to have fewer hairs on the 

 3rd and 4th segments (if dorsal tubercles here are really 

 anterior trapezoidals) and more on 5th, gth, and 12th. On 

 the remaining segments 6. 7. 8. 10 and 11, vcuosa has three 

 hairs on the anterior trapezoidal tubercles, rumicis has three 

 strong hairs and two faint ones, menyanthidis has five, myriccB 

 six, and auricovia seven. So that here we have a decided 

 means of distinguishing them, but by no means so simple in 

 application as the plain statement of the numbers suggests, a 

 correct enumeration being indeed very difficult unless the larva 

 is chloroformed, or, in effect, in some other way killed. 



Figures 8 and g are the larvae of Bisulcia ligiistri in their first 

 skins. This larva is a true Acronycta, the nth segment being 

 pale and " weak," the paleness is here no especial feature, as 

 none of the segments are dark, but the " weakness " and form 

 are distinctive, it is smaller than the others, chiefly by being 

 lower dorsally, and weaker by the much smaller tubercles. It 

 also presents the tendency to a lateral projection, well shown 

 in fig. 8, which is always most pronounced in the larva when 

 newly hatched, and is therefore best seen in the figures of 

 larvas of Viviinia that are taken from the youngest larvae, viz., 

 fig. I, auriconia, fig. 6, veiiosa. In this larva each tubercle, 

 anterior trapezoidal as well as the rest, has only one hair. 



Fig. 10, aceris, had space permitted, ought to have been in 

 Plate VI. with the other Qispidia larvae. This figure is from a 

 larva almost newly hatched ; it shows well the characteristic 

 Acronycta form of the nth segment as regards having a lateral 

 expansion. The pale segments here are 6. 10 and 11. 

 {To be continued.) 



Scientific notes. 



Variation associated with change of constitution (diseasr?) 

 IN Acronycta alni. — I have bred A. aini for several years, have 

 always found it rather shy as to breeding, and, each year, have ob- 

 served several instances of useless pairing. But this year (1890), though 



