Hemipsocidae

Introduction

Hemipsocidae includes nearly 50 species in 4 genera worldwide.  The family is found primarily in the tropics.  Most diversity in Hemipsocidae has been found in China, where the family is most actively studied.  Two species are known from North America: Hemipsocus choroticus from Florida and coastal regions Texas and North Carolina, and H. pretiosus from Florida.

Hemipsocids live in dead foliage and when disturbed, they tend to run rapidly or tumble in a characteristic manner.

Characteristics

Synapomorphies

• Head lacks epistomal suture.
• Forewing vein M has two branches.
  
• Forewing veins CuA1 and M are connected by a crossvein.
  
• Male lacks aedeagus on phallosome (likely synapomorphy).
  

General Characters

• Head:  Antennae have 13 segments.
  
• Legs: Tarsi have 2 segments.
  
• Wings:
  
• Forewing with characteristic appearance: 
• Vein M has 2 branches.
• Forewing has single anal vein.
  
• Areola postica is connected to vein M by a crossvein.
• Hairs on forewing are bristly and widely spaced.
• Hairs on veins are in a single row (if present).
  
• In several species, setae on veins arise from dark spots.
• Hindwing margin has hairs all around, but veins lack hairs.
  
• Males: 
  
• Phallosome is very simple and in form of posteriorly open frame.
• Paraproct has a cone-shaped distal projection.
• Female: 
  
• Gonapophyses are complete and very strongly sclerotised:
• Dorsal valve is broad and pointed.
• Ventral valve is broad and pointed.  
  
• External valve is very large and triangular with a few hairs.
• Eggs: Eggs are smooth and encrusted with debris.
  

How to Know the Family

• Antennae have 13 segments.
• Tarsi have 2 segments.
• Forewing vein M has two branches.
• Forewing veins CuA1 and M are connected by a crossvein.
• In several species, setae on veins arise from dark spots.

Discussion of Phylogenetic Relationships

The monophyly of genus Hemipsocus is supported by molecular data (4 species; Johnson et al. 2004), which places the genus in infraorder Psocetae.  Morphological data, however, place Hemipsocidae alone in infraorder Hemipsocetae based on these morphological synapomophies: CuA1-M crossvein in forewing, M vein two-branched in forewing, absence of epistomal suture on head, and first axillary sclerite at wing base apically broadened (Yoshizawa 2002).  Further study is needed to clarify the relationships of Hemipsocidae with other families.

References

Johnson, K. P. & E. L. Mockford. 2003. Molecular Systematics of Psocomorpha (Psocoptera). Systematic Entomology 28: 409-40.

Johnson, K. P., K. Yoshizawa, and V. S. Smith. 2004. Multiple origins of parasitism in lice. Proceedings of the Royal Society of London B 271:1771-1776.

Lienhard, C. and C. N Smithers. 2002. Psocoptera (Insecta) World Catalogue and Bibliography. Muséum d'Histoire Naturelle, Geneva, Switzerland.

Mockford, E. L. 1993. North American Psocoptera (Insecta). Gainesville, Florida: Sandhill Crane Press.

New, T.R. 2005. Psocids, Psocoptera (Booklice and barklice), 2nd edition: Handbooks for the Identification of British Insects. Vol. 1, Part 7. Royal Entomological Society, London, UK.

Smithers, C. N. 1996. Psocoptera. Pp. 1-80, 363-372 (Index) in Wells A. (ed.) Zoological Catalogue of Australia. Vol. 26. Psocoptera, Phthiraptera, Thysanoptera. Melbourne: CSIRO Publishing, Australia.

Yoshizawa, K. 2002. Phylogeny and higher classification of suborder Psocomorpha (Insecta: Psocodea:'Psocoptera'). Zoological Journal of the Linnean Society 136: 371-400.