39 



Essig is quoted as saying that it is very probable that the same 

 dimorphic forms exist in Pseudococciis artemisiae. The author, having 

 examined the types, of this species, finds it identical with Erium 

 lichtensioides, CklL, a species that has but one generation in a year 

 in the neighbourhood of Stanford University. There occurs, however, 

 upon the same host a species of Pseudococcus, at present undetermined, 

 that may have given rise to the confusion. 



A case of seasonal dimorphism in Phenacoccus acericola was recorded 

 by King. The author attributes this statement to confusion of 

 P. acericola with P. comstocki, Kuw., which occurs on maple in the 

 eastern States. Pseudococcus trifolii, Forbes, has similarly been 

 described as having dimorphic forms, but it is probable that this 

 is also a case of confusion with another species, P. maritimus, Ehrh. 



KoEPKE (W. ). Mertilia malayensis, Dist., een " Bloemwants " (Capside) 

 schadelijk voor Orchideen. [Mertilia malayensis, Dist., a Capsid 

 injurious to Orchids.] — Teysmannia, Batavia, iv, 1918, pp. 201-212, 

 4 plates. 



In December 1917 an orchid-grower applied to the Salatiga Station 

 (Java) for advice regarding a pest which was identified as the Capsid, 

 Mertilia malayensis, Dist., described in 1904 from the Malay Peninsula, 

 but hitherto imrecorded from the Malay Archipelago, where however 

 it appears to be widespread in Java and where M. brevicornis, Popp., 

 and M. ternatensis, Dist., have also been observed. 



All stages of M. ynalayensis are briefly described. Like other 

 Capsids it deposits its eggs in the plant-tissue, but very near the surface. 

 They are exceptionally difi&cult to find even when abundant. The 

 duration of the egg-stage is not known. The first moult takes place 

 immediately after the larva hatches and before it begins to feed, and 

 another five or six moults occur before the adult stage is reached. 

 The larvae are gregarious. Adults were obtained on 1st and 2nd 

 March 1918 from larvae hatched on 1st February, four weeks earlier. 

 The weather was cool and damp and this probably retarded develop- 

 ment. Adults were observed to live for over two months. Both 

 larvae and adults are very shy, and if disturbed for any length of time 

 the former disappear among the orchid roots, while the latter, which 

 are not ready flrers, take to wing. M. malayensis is most easily 

 caught in the morning when torpid with the cold. At mid-day it 

 shelters in the shade. No natural enemies were observed. The 

 injury is due to the numerous punctures on both sides of the leaves, 

 on the flower-stalks and on the roots. The leaves turn yellow and 

 fall. If the insects disappear entirely the plant may recover, but 

 growth will be seriously retarded. M. malayensis is therefore a 

 dangerous pest of orchids, especially Phalaenopsis amahilis. 



Spraying with an American contact poison, Harbas oil. proved 

 ineffective, but surprising results were obtained with a stomach 

 poison used in East Africa against the coffee bug [Antestia variegota], 

 namely, sodium arsenite 3|-5 oz., 3|-5 pints warm water, 2 lb. sugar 

 or molasses. Within an hour several Capsids were dead and all in 

 the cage had perished by the next day. Unfortunately the orchids 

 also died within a fortnight. Further experiments could "not be under- 

 taken, and collection, as practised against Helopeltis, is advised. 



