Maskell. — On the " Honeydew " of Coccidfe. 48 



such as Aspidiotiis, Ctenochiton, Inglisia, Eriococcus, etc., the 

 character of the shield or test, waxy or cottony or felted, would 

 prevent the honeydew from exuduig anywhere but at the 

 abdominal extremity ; there, however, there is almost always 

 some kind of orifice or cleft permitting the extrusion of the 

 excreting organ. 



A point of considerable economic importance is connected 

 with this honeydew of Coccids, namely, the growth upon it of 

 various fungi ; and I take this opportunity of drawing the atten- 

 tion of farmers and tree-growers to it, as I believe that a good 

 deal of misconception exists in its regard. Everybody, doubt- 

 less, has observed how, in gardens or in greenhouses, in planta- 

 tions or in forests, many plants have an unpleasantly blackened 

 appearance ; and it fi-equently happens that the true colours of 

 the twigs and leaves are much, if not quite, obscured by the 

 black coating on them (see figs. 2a and 2h). Now, it wild 

 generally be observed that this black coating is in most cases 

 thicker and more unsightly on the lower than on the upper 

 leaves and branches : sometimes, indeed, the uppermost leaves 

 will be bright green, whilst the lowest look as if they were 

 covered with soot. It will also be noticed that the black 

 coating is abundant, not only in the damp recesses of the forest, 

 but also in comparatively dry greenhouses, and just as much so 

 in open-air gardens. 



The primary cause of this is usually the presence of some 

 homopterous insects, whether Aphididce, Psi/llidce, Coccida or 

 others. The "honeydew" excreted by them drops, or in the 

 case of Coccids falls in spray, over the leaves beneath them : it 

 very soon furnishes a glutinous and congenial soil for the spores 

 of fungi. If one may judge from the quantity of black coating 

 often found, the act of excretion above described must be 

 repeated somewhat frequently, though so seldom observed. 



As to the question, what is this black sooty coating : there is 

 no doubt of its fungoid character, but I am not able to identify 

 it precisely. There seem to be, in fact, several species in it. 

 On the leaves, the fungus forms usually a flat, black, thinnish, 

 closely woven covering ; on the twigs and stem it has a looser 

 texture, and generally forms a mass of small erect threads (see 

 figs. 2« and 2b). These appearances are by no means confined to 

 New Zealand, and most writers on Coccidse devote some phrases 

 in passing to the fungus. Signoret* calls it '^ fumagine i" 

 Comstock f calls it " Fuma go salicina :" in an early paper of 

 mine (1878) I attributed it to " Antennaria." In point of fact, a 

 good many of the Hyphomycetos and Physomycetes may be 

 found amongst this fungoid growth. I have attached to this 



* " Essai sur les Cocheuilles."' 



t Report of the Entomologist, U.S. Department of Agric, 1880. 



